4 men and 5 women can complete a work in 15 days, whereas 9 men and 6 women can complete it in 10 days. To complete the same work in 7 days, how many women should assist 4 men?
Show answer & explanation
Correct answer: D
Explanation
The correct answer is option 4 i.e. 13
Let the efficiency of 1 man and 1 woman be 'm' units and 'w' units.
According to the question,
(4m + 5w) × 15 = (9m + 6w) × 10
w = 2m.
The efficiency of a woman is twice of a man.
Total work in terms of women = (2w + 5w) × 15 = 105w
Now.
⇒ (x × w + 4m) × 7 = 105w
⇒ 7wx + 14w) = 105w
⇒ 7wx = 91w
⇒ x = 13 days.