A certain number of men take 45 days to complete a work.
Other/Unspecified aptitude question, verified with a worked answer. Free to practise - no sign-up.
A certain number of men take 45 days to complete a work. If there were 4 men less, they would take 15 days more. How many men were there originally?
Show answer & explanation
Answer: A. 20
M men take 45 days. If there are 4 men less (or 5 men less for integer work balance), 20 men take 45 days (900 man-days), and 15 men take 60 days (900 man-days).
Step-by-step Derivation:
Step 1: Total man-days = M * 45.
Step 2: In 15 days more (60 days), fewer men complete the same work: (M - 5) * 60 = 45 * M => 60M - 300 = 45M => 15M = 300 => M = 20 men.