A and B undertake a piece of work for Rs. 250 . A alone can do that work in 5 days and B alone can do that work in 15 days . With the help of C, they finish the work in 3 days . If every one gets paid in proportion to work done by them, the amount C will get is

Let total work to be done = 15 units

A alone can do the work in 5 days, => A's efficiency = $$\frac{15}{5}=3$$ units/day

Similarly, B's efficiency = $$\frac{15}{15}=1$$ unit/day

Let C's efficiency = $$x$$ units/day

=> (A+B+C)'s 1 day's work = $$3+1+x=(4+x)$$ units/day

All the three finish the work in 3 days

=> $$3 \times (4+x)=15$$

=> $$4+x=\frac{15}{3}=5$$

=> $$x=5-4=1$$

Thus, ratio of efficiency of A : B : C = 3 : 1 : 1

Total amount = Rs. 250

$$\therefore$$ Amount C will get = $$\frac{1}{(3+1+1)} \times 250$$ 

= $$\frac{250}{5}=Rs.$$ $$50$$

=> Ans - (A)