Question

1. A can do a work in 14 days and working together a and b can do the same work in 10 days. In what time can b alone do the work?

Answer 1

Answer:

1 day work of A=1/14

1 day work of (A+B)=1/10

Given:A+B=1/10

or,1/14+B=1/10

or,B=1/10-1/14

Or,B=2/70=1/35

Now, 1/35 part of work is done in 1 day by B.

So,1 work will be done in 1÷1/35=35 days.

B can alone do the work in 35 days.

Answer 2

A can complete the work in 14 days

So, A's 1 day's work = 1/14

A and B can complete the same work in 10 days

So, A and B 1 day's work = 1/10

Let the days taken to complete the same work By B be x

B's 1day work = 1/x

Equation formed :

$\frac{1}{10} - \frac{1}{14} = \frac{1}{x}$

$\frac{1 \times 7}{10 \times 7} - \frac{1 \times 5}{14 \times 5} = \frac{1}{x}$

$\frac{7}{70} - \frac{5}{70} = \frac{1}{x}$

$\frac{2}{70} = \frac{1}{x}$

$\frac{70}{2} = x$

$x = 35$

So, B alone can do the same work in 35 days.