1200 men and 500 women can build a bridge in 2 weeks. 900 men and 250 women will take 3 weeks to build the same bridge. How many men will be needed to build the bridge in one week? A. 3000 B. 3300 C. 3600 D. 3900

GATE 2017 · General Aptitude · Work Time · medium

Answer: 3600 men are needed to build the bridge in one week (Option C).

1. Write work equations: Eq1: 2400m + 1000w = 1. Eq2: 2700m + 750w = 1.
2. Eliminate w: 3×Eq1: 7200m + 3000w = 3. 4×Eq2: 10800m + 3000w = 4. Subtract: 3600m = 1, so m = 1/3600.
3. Find number of men for 1 week: N × (1/3600) = 1 => N = 3600.