Question

plz slove this.......

Answer 1

required time is in the attachment

$\frac{1}{10} + \frac{1}{30} - \frac{1}{20} =$
$\frac{6 + 2 - 3}{60}$
$= \frac{5}{60}$
$= \frac{1}{12}$
hence time taken is 12 min