Average Aptitude Test Paper 26) Average age of a group of 30 boys is 16 years. A boy of age 19 leaves the group and a new boy joins the group. If the new average age of the group is 15.8 years, find the age of the new boy.
The correct answer is B Explanation: Let the age of new boy = X years Total age of 30 boys = 30*16 = 480 years As per question, if we minus age of boy who leaves the group and then add the age of boy who joins the group the new average becomes = 15.8 years. ∴ = 15.8 480  19 + X = 474 X = 474  480 +19 X =  6 +19 = 13 years 7) The average weight of 10 men is decreased by 2 kg when one of them whose weight is 60 kg is replaced by a new man. What is the weight of the new man?
The correct answer is B Explanation: Average decrease in weight per person = 2kg There are 10 men so total decrease in weight on replacing a man with a new man = 10 ∗ 2= 20 kg Weight of the man who is replaced = 60 kg ∴The weight of the new man would be = Weight of man replaced  total decrease in weight of the group of 10 men. = 60  20 = 40 kg 8) The average age of 30 boys in a class is 15 years. If we include the age of two teachers the average age increases by 1. Find the sum of ages of the two teachers.
The correct answer is C Explanation: Total age of 30 boys would be = 30∗15 = 450 years Total age of 30 boys and 2 teachers would be = 32∗16= 512 years ∴ Sum of ages of two teachers would be = 512  450 = 62 years 9) The average age of the committee of 10 members is 40 years. A member of age 52 retires and a new member of age 38 takes his place. What is the average age of the present committee?
The correct answer is A Explanation: Total age of the committee = 10 ∗ 40 = 400 years Age of retired member = 52 years Age of new member = 38 years As per question, we will minus 52 years and add 38 years in the total age then divide by 10 to find the new average age of the committee. ∴ = = = = 38.6 years 10) Four years ago, the average age of A and B was 20 years. If today average age of A, B and C is 25 years, what will be age of C after 7 years?
The correct answer is B Explanation: Total age of A and B four years ago = 20 ∗ 2 = 40 years Present total age of A and B would be = 40 + 4∗2 = 48 years Present total age of A, B and C is = 25 ∗ 3 = 75 years ∴ Present age of C would be = 75  48 = 27 years Age of C after 7 years = 27 + 7 = 34 years Average Aptitude Test Paper 1 Average Aptitude Test Paper 3 Average Aptitude Test Paper 4 Average Aptitude Test Paper 5 Average Aptitude Test Paper 6 Average Aptitude Test Paper 7 Average Aptitude Test Paper 8
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