Time and Work - Quantitative Aptitude (MCQ) questions for Q. 81
Q. 12 men and 18 boys working 7.5 minutes an hour complete a particular piece of work in 60 hours. If a boy’s work is half as efficient as a man’s work, how many boys will be needed to help 21 men to achieve twice the work in 50 hours working 9 minutes in an hour. - Published on 15 Jun 15a. 42
b. 46
c. 48
d. 38
ANSWER: 42
1 man is equivalent to 2 boys in work capacity. 12 men + 18 boys = 12 x 2 + 18 = 42 boys.
Let the required number of boys be x. So Total number of people doing work = 21 men x 2 (according to work capacity) + x boys.
Taking respective ratios as required:
Given:
=> Hours 50:60
=> Minutes per hour 9: 15/2
=> Work 1:2
=> People: 42: 42 + x
=> 50 x 9 x 1 x (42+x) = 60 x 15/2 x 2 x 42
=> 42 +x = 84
x = 42
