Question Number 76536 by byaw last updated on 28/Dec/19
Commented by benjo 1/2 santuyy last updated on 28/Dec/19
$${good}\:{luck}\:{to}\:{sir} \\ $$
Answered by john santu last updated on 28/Dec/19
$${using}\:{the}\:{formula}\::\:\frac{\mathrm{1}}{{x}}=\frac{\mathrm{1}}{\mathrm{30}}+\frac{\mathrm{1}}{\mathrm{15}}+\frac{\mathrm{1}}{\mathrm{10}} \\ $$$$\frac{\mathrm{1}}{{x}}=\frac{\mathrm{1}+\mathrm{2}+\mathrm{3}}{\mathrm{30}}=\frac{\mathrm{6}}{\mathrm{30}}\rightarrow{x}=\mathrm{5}\:{minutes} \\ $$