1. Find the average of all prime numbers between 30 and 50?

2. Find the average of first 40 natural numbers?

3. Find the average of first 20 multiples of 7?

4. The average of four consecutive even numbers is 27. Find the largest of these numbers?

5. There are two sections A and B of a class consisting of 36 and 44 students respectively. If the average weight of section A is 40kg and that of section B is 35kg, find the average weight of the whole class?

6. Nine persons went to a hotel for taking their meals 8 of them spent Rs.12 each on their meals and the ninth spent Rs.8 more than the average expenditure of all the nine. What was the total money spent by them?

7. Of the three numbers, second is twice the first and is also thrice the third. If the average of the three numbers is 44.Find the largest number.

8. The average of 25 results is 18.The average of 1st 12 of them is 14 & that of last 12 is 17.Find the 13th result.

9. The Average of 11 results is 16, if the average of the 1st 6 results is 58 & that of the last 63. Find the 6th result.

10. The average weight of A, B, C is 45 Kg. The average weight of A & B be 40Kg & that of B,C be 43Kg. Find the weight of B.

11. The average age of a class of 39 students is 15 years. If the age of the teacher be included, then the average increases by3 months. Find the age of the teacher.

12. The average weight of 10 oarsmen in a boat is increased by 1.8 kg when one of the crew, who weighs 53 kg is replaced by a new man. Find the weight of the new man.

13. There were 35 students in a hostel. Due to the admission of 7 new students, the expenses of the mess were increased by Rs. 42 per day while the average expenditure per head diminished by Rs 1. What was the original expenditure of the mess?

14. A batsman makes a score of 87 runs in the 17th inning and thus increases his average by 3. Find his average after 17th inning.

15. Distance between two stations A and B is 778 km. A train covers the journey from A to B at 84 km per hour and returns back to A with a uniform speed of 56 km per hour. Find the average speed of the train during the whole journey.

16. The average of 20 numbers is zero. Of them at the most, how many may be greater than zero ?

17. In Arun's opinion, his weight is greater than 65 kg but less than 72 kg. His brother does not agree with Arun and he thinks that Arum's weight is greater than 60 kg but less than 70 kg. His mother's view is that his weight cannot be greater than 68 kg. If all of them are correct in their estimation, what is the average of different probable weights of Arun?

18. If the mean of 5 observations x, x + 2, x + 4, x + 6 and x+ 8 is 11, then the mean of the last three observations is :

19. If the mean of a, b, c is M and ab + bc + ca = 0, then the mean of a

^{2}, b^{2}, c^{2}is :
20. The average of the two-digit numbers, which remain the same when the digits interchange their positions, is :

21. The mean of 1

^{2}, 2^{2}, 3^{2}, 4^{2}, 5^{2}, 6^{2}, 7^{2}is :
22. The average of a non-zero number and its square is 5 times the number. The number is :

23. The average of 7 consecutive numbers is 20. The largest of these numbers is :

24. The sum of three consecutive odd numbers is 38 more than the average of these numbers. What is the first of these numbers?

25. The average age of the boys in a class is 16 years and that of the girls is 15 years. The average age for the whole class is :

Ans: Cannot be computed with the given information

26. The average annual income (in Rs.) of certain agricultural workers is S and that of other workers is T The number of agricultural workers is 11 times that of other workers. Then the average monthly income (in Rs.) of all the workers is :

27. A family consists of grandparents, parents and three grandchildren. The average age of the grandparents is 67 years, that of the parents is 35 years and that of the grandchildren is 6 years. What is the average age of the family?

28. A library has an average of 510 visitors on Sundays and 240 on other days. The average number of visitors per day in a month of 30 days beginning with a Sunday is :

29. The average of five consecutive odd numbers is 61. What is the difference between the highest and lowest numbers?

30. If the average marks of three batches of 55, 60 and 45 students respectively is 50, 55 and 60, then the average marks of all the students is :

31. A car owner buys petrol at Rs 7.50, Rs. 8 and Rs. 8.50 per litre for three successive years. What approximately is the average cost per litre of petrol if tie spends Rs. 4000 each year?

32. The average weight of 16 boys in a class is 50.25 kgs and that of the remaining 8 boys is 45.15 kgs. Find the average weight of all the boys in the class.

33. Out of 9 persons, 8 persons spent Rs. 30 each for their meals. The ninth one spent Rs. 20 more than the average expenditure of all the nine. The total money spent by all of them was :

34. The average of 50 numbers is 30. If two numbers, 35 and 40 are discarded, then the average of the remaining numbers is nearly :

35. The average of six numbers is x and the average of three of these is y. If the average of the remaining three is z, then :

36. 16 children are to be divided into two groups A and B of 10 and 6 children. The average percent marks obtained by the children of group A is 75 and the average percent marks of all the 16 children is 76. What is the average percent mark of children of group B?

37. The average of five numbers is 27. If one number is excluded, the average becomes 25. The excluded number is :

38. The average age of 35 students in a class is 16 years. The average age of 21 students is 14. What is the average age of remaining 14 students?

39. The average of six numbers is 3.95. The average of two of them is 3.4, while the average of the other two is 3.85. What is the average of the remaining two numbers?

40. The average score of a cricketer for ten matches is 38.9 runs. If the average for the first six matches is 42, then find the average for the last four matches.

41. The batting average for 40 innings of a cricket player is 50 runs. His highest score exceeds his lowest score by 172 runs. If these two innings are excluded, the average of the remaining 38 innings is 48 runs. The highest score of the player is :

42. The average price of 10 books is Rs. 12 while the average price of 8 of these books is Rs. 11.75. Of the remaining two books, if the price of one book is 60% more than the price of the other, what is the price of each of these two books?

43. A company produces on an average 4000 items per month for the first 3 months. How many items it must produce on an average per month over the next 9 months, to average 4375 items per month over the whole?

44. In the first 10 overs of a cricket game, the run rate was only 3.2. What should be the run rate in the remaining 40 overs to reach the target of 282 runs?

45. The average of runs of a cricket player of 10 innings was 32. How many runs must he make in his next innings so as to increase his average of runs by 4?

46. A grocer has a sale of Rs. 6435, Rs. 6927, Rs. 6855, Rs. 7230 and Rs. 6562 for 5 consecutive months. How much sale must he have in the sixth month so that he gets an average sale of Rs. 6500?

47. The average price of three items of furniture is Rs. 15000. If their prices are in the ratio 3:5:7, the price of the cheapest item is :

48. Of the four numbers, whose average is 60, the first is one-fourth of the sum of the last three. The first number is :

49. Of the four numbers, the first is twice the second, the second is one-third of the third and the third is 5 times the fourth. The average of the numbers is 24.75. The largest of these numbers is :

50. Of the three numbers, the first is twice the second and the second is twice the third. The average of the reciprocal of the numbers is

51. Of the three numbers, the average of the first and the second is greater than the average of the second and the third by 15. What is the difference between the first and the third of the three numbers?

52. The average of 8 numbers is 20. The average of first two numbers is 15 ½ and that of the next three is 21 1/3. If the sixth number be less than the seventh and eighth numbers by 4 and 7 respectively, then the eighth number is :

53. If the arithmetic mean of seventy-five numbers is calculated, it is 35, If each number is increased by 5, then mean of new numbers is :

54. Average of ten positive numbers is 7. If each number is increased by 12. Then average of the new set of numbers is:

55. The mean of 50 observations was 36. It was found later that an observation 48 was wrongly taken as 23. The corrected new mean is :

56. A pupil's marks were wrongly entered as 83 instead of 63. Due to that the average marks for the class got increased by half. The number of pupils in the class is :

57. The average age of 15 students of a class is 15 years. Out of these, the average age of 5 students is 14 years and that of the other 9 students is 16 years. The age of the 15th student is :

58. The average of 11 numbers is 10.9. If the average of the first six numbers is 10.5 and that of the last six numbers is 11.4,then the middle number is :

59. The average weight of three boys A, B and C is 54 1/3 kg, while the average weight of three boys B, D and E is 53 kg. What is the average weight of A, B, C, D and E?

60. The average temperature of the town in the first four days of a month was 58 degrees. The average for the second, third, fourth and fifth days was 60 degrees. If the temperatures of the first and fifth days were in the ratio 7 : 8, then what is the temperature on the fifth day ?

61. The average weight of A, B and C is 45 kg. If the average weight of A and B be 40 kg and that of B and C be 43 kg, then the weight of B is :

62. The average monthly salary of 20 employees in an organisation is Rs. 1500. If the manager's salary is added, then the average salary increases by Rs. 100. What is the manager's monthly salary?

63. The average monthly income of P and Q is Rs. 5050. The average monthly income of Q and R is Rs. 6250 and the average monthly income of P and R is Rs. 5200. The monthly income of P is :

64. The average age of 36 students in a group is 14 years. When teacher's age is included to it, the average increases by one. What is the teacher's age in years?

65. The average weight of a class of 24 students is 35 kg. If the weight of the teacher be included, the average rises by 400 g. The weight of the teacher is :

66. The average age of the mother and her six children is 12 years which is reduced by 5 years if the age of the mother is excluded. How old is the mother?

67. The captain of a cricket team of 11 members is 26 years old and the wicket keeper is 3 years older. If the ages of these two are excluded, the average age of the remaining players is one year less than the average age of the whole team. What is the average age of the team?

68. The average weight of 45 students in a class is 52 kg, Five of them whose average weight is 48 kg leave the class and other 5 students whose average weight is 54 kg join the class. What is the new average weight (in kg) of the class?

69. The average weight of 8 persons increases by 2.5 kg when a new person comes in place of one of them weighing 65 kg. What might be the weight of the new person?

70. The average height of 25 boys is 1.4 m. When 5 boys leave the group, then the average height increases by 0.15 m. What is the average height of the 5 boys who leave?

71. The average of five consecutive numbers is n. If the next two numbers are also included, the average will :

72. A cricketer has a certain average for 10 innings. In the eleventh inning, he scored 108 runs, thereby increasing his average by 6 runs. His new average is :

73. The average age of 8 men is increased by 2 years when two of them whose ages are 21 years and 23 years are replaced by two new men. The average age of the two new men is :

74. A motorist travels to a place 150 km away at an average speed of 50 km / hr and returns at 30 km / hr. His average speed for the whole journey in km / hr is :

75. A team of 8 persons joins in a shooting competition. The best marksman scored 85 points. If he had scored 92 points, the average score for the team would have been 84. The number of points, the team scored was :

76. A cricketer whose bowling average is 12.4 runs per wicket takes 5 wickets for 26 runs and thereby decreases his average by 0.4. The number of wickets taken by him till the last match was :

77. The average weight of 3 men A, B and C is 84 kg. Another man D joins the group and the average now becomes 80 kg. If another man E, whose weight is 3 kg more than that of D, replaces A, then the average weight of B, C, D and E becomes 79 kg. The weight of A is :

78. The average age of husband, wife and their child 3 years ago was 27 years and that of wife and the child 5 years ago was 20 years. The present age of the husband is :

79. 3 years ago, the average age of a family of 5 members was 17 years. A baby having been born, the average age of the family is the same today. The present age of the baby is :

80. The average age of a husband and his wife was 23 years at the time of their marriage. After five years they have a one-year old child. The average age of the family now is :

81. Three years ago, the average age of A and B Was 18 years. With C joining them, the average age becomes 22 years. How old is C now?

82. 10 years ago, the average age of a family of 4 members was 24 years. Two children having been born (with age difference of 2 years), the present average age of the family is the same. The present age of the youngest child is :

83. After replacing an old member by a new member, it was found that the average age of five members of a club is the same as it was 3 years ago. What is the difference between the ages of the replaced and the new member?

84. A certain factory employed 600 men and 400 women and the average wage was Rs. 25.50 per day. If a woman got Rs. 5 less than a man, then what are their daily wages?

85. The arithmetic mean of the scores of a group of students in a test was 52. The brightest 20% of them secured a mean score of 80 and the dullest 25% a mean score of 31. The mean score of remaining 55% is :

86. The average salary of all the workers in a workshop is Rs. 8000. The average salary of 7 technicians is Rs. 12000 and the average salary of the rest is Rs. 6000. The total number of workers in the workshop is :

87. The average age of 3 children in a family is 20% of the average age of the father and the eldest child. The total age of the mother and the youngest child is 39 years. If the father's age is 26 years, what is the age of second child?

88. During the recent incessant and unprecedented rains in Chennai, the average rain fall on Wednesday, Thursday and Friday was 25cm. The average rainfall on Thursday, Friday and Saturday was 24cm. if the rainfall Saturday was 27cm, what was cm rain fall on Wednesday

89. Eesha is a freelance programmer working in a mission critical project approaching go-live. Due to pressing deadline, she had to work continuously for 15 hours to support the activities. Her employer pays freelance programmers different hourly rates depending on the nature of work done in every hour. Her average earning during these 15 hours was $90/hour. During her first 7 hours, her average earning was $87/hour and average earning in her last 7 hours was $92/hour. What was Eesha’s earning($) in the 8

^{th}hour?
90. The average age of a class of 22 students is 21 years. The average increased by 1 when the teacher’s age is included. What is the age of the teacher?

91. The average temperature of June, July and August was 31 degrees. The average temperature of July, August and September was 30 degrees. If the temperature of June was 32 degrees, find the temperature of September(degrees)

92. The average temperature of a kiln on Tuesday, Wednesday and Thursday was 430 degrees Celsius. The average temperature of the kiln on Wednesday, Thursday and Friday was 496 degrees Celsius. If the average temperature of the kiln on Friday was 451 degrees Celsius, find the temperature in degree Celsius on Tuesday?