3 men and 4 women can do a work in 7 days, whereas 2 men and 1 woman can do it in 14 days. 7 women will complete the same work in:

Correct option is B

Given:

3 men and 4 women can finish a work in 7 days.

2 men and 1 women can finish same work in 14 days

Formula Used:

Work done = $$Number \ of \ workers \times Efficiency \ of\ each \ worker\times Time$$​​

Solution:

Let the efficiency of a man and a boy be M and W respectively.

According to the question,

​$$(3 \times M + 4 \times W) \times 7 = (2 \times M + 1 \times W) \times 14$$​​

M = 2W

Total work is:

​$$(3\times 2W + 4 \times W) \times 7$$​​

​$$10W \times 7$$​​

= 70W

Time taken by 7 women will be = $$\frac{70W}{7} = 10days$$​​