# Question #e0522

Jun 4, 2016

c) 15

#### Explanation:

Let B complete the job in days$= x$
$\therefore$ B can do alone in $1$ day$= \frac{1}{x}$ job

A can do alone in $1$ day$= \frac{1}{10}$ job
Combining both
Both A and B can do in $1$ day$= \frac{1}{10} + \frac{1}{x}$ job
Given is that both A and B can do in $1$ day$= \frac{1}{6}$ job
Equating both we obtain
$\frac{1}{10} + \frac{1}{x} = \frac{1}{6}$
Solving for $x$
$\frac{1}{x} = \frac{1}{6} - \frac{1}{10}$
$= \frac{5 - 3}{30}$
$= \frac{1}{15}$
or $x = 15$