Question Number 25377 by Mr eaay last updated on 09/Dec/17
Answered by mrW1 last updated on 09/Dec/17
$$\frac{\mathrm{1}}{\mathrm{15}}+\frac{\mathrm{1}}{\mathrm{12}}=\frac{\mathrm{4}+\mathrm{5}}{\mathrm{60}}=\frac{\mathrm{3}}{\mathrm{20}} \\ $$$$\frac{\mathrm{20}}{\mathrm{3}}\approx\mathrm{7} \\ $$$$\Rightarrow{in}\:\mathrm{7}\:{days}\:{the}\:{work}\:{will}\:{be} \\ $$$${completed}. \\ $$