If 2 men or 3 women can finish a piece of work in 15 days. In how many days can 6 men and 9 women together do the same piece of work?

Correct option is D

Given:

​2 men or 3 women can finish a piece of work in 15 days  

Solution:

Fast we find efficiency 

2M$$\times$$15D = 3W$$\times$$15D

2M = 3W

$$\frac{M}{W}$$ = $$\frac32$$​​

Now we find total work

2$$\times$$3 $$\times$$15 = 90

6M+9W efficiency =$$(6\times3)+(9\times2)$$​,  (18)+(18)= 36

​$$\frac{90}{36}$$ = $$\frac{10}{4}$$ = $$\frac{5}{2}$$ =$$2\frac{1}{2}$$ 

Option (d)