Question

If 5 persons can do a piece of work in 10 days, then in how many days 2 persons will complete the work?

Answer 1

$\because 5$ persons can do a piece of work in 10 days.

$\therefore \quad 1$ person can do a piece of work in $10 \times 5$ days.

$\therefore 2$ persons can do a pece of work in $=\frac{10 \times 5}{2}=25$ days; Ans.

Trick : $D_{2}=\frac{M_{1} D_{1}}{M_{2}}=\frac{5 \times 10}{2}$ $=25$ days; Ans