Discussion Forum

A, B and C can do a piece of work in 20, 30 and 60 days respectively. In how many days can A do the work if he is assisted by B and C on every third day ?

Answer:

Explanation:

A's $2$ day's work $=\left(\frac{1}{20}\times 2\right)$ $=\frac{1}{10}$.

$(A+B+C)'s$ $1$ day work $=\left(\frac{1}{20}+\frac{1}{30}+\frac{1}{60}\right)$ =$\frac{1}{10}$.

Work done in $3$ days $=\left(\frac{1}{10}+\frac{1}{10}\right)$ $=\frac{1}{5}$.

Now, $\frac{1}{5}$ work is done in $3$ days.

$\therefore$ Whole work will be done in $(3\times 5)$ = 15 days.