12 men or 30 boys can complete a work in 72 days. How many days will 48 men and 24 boys will take to complete the same work?

Let time taken by 1 man to complete unit work = $$m$$ and by 1 boy = $$bb$$

12 men complete the work in 72 days, => $$m=\frac{1}{12\times72}$$

Similarly, $$b=\frac{1}{30\times72}$$

Now, time taken by 48 men and 24 boys to complete unit work = $$48m+24b$$

= $$(48\times\frac{1}{12\times72})+(24\times\frac{1}{30\times72})$$

= $$\frac{1}{18}+\frac{1}{90}$$

= $$\frac{5+1}{90}=\frac{1}{15}$$

$$\therefore$$ No. of days taken to finish the work = 15

=> Ans - (C)