P can complete 1/4 of a work in 10 days, Q can complete 40% of the same work in 145 days. R, complete 1/3 of the work in 13 days and S, 1/6 of the work in 7 days. Who will be able complete the work first ?

Answer: Option C

P completes $$\frac{1}{4}$$ of work in 10 days
P completes full of work in
$$\begin{array}{rl}& =\frac{10}{1}\times 4\\ & =40\text{ days}\end{array}$$
Q completes 40% of work in 145 days
Q completes full 100% of work in
$$\begin{array}{rl}& =\frac{145}{40}\times 100\\ & =362.5\text{ days}\end{array}$$
R completes $$\frac{1}{3}$$ of work in 13 days
R completes full of work in
$$\begin{array}{rl}& =\frac{13}{1}\times 3\\ & =39\text{ days}\end{array}$$
S completes $$\frac{1}{6}$$ of work in 7 days
S completes full of work in
$$\begin{array}{rl}& =\frac{7}{1}\times 6\\ & =42\text{ days}\end{array}$$
Clearly, we can see R completes the work first