Question

A and B complete a work in 15 day and A in 20 days find b can do the work​

Answer 1

Answer:

gyan prakash verma

Step-by-step explanation:

$a + b = \frac{1}{15} days. \\ a = \frac{1}{20} days. \\ so \: \\ b = (a + b) - a. \\ b = \frac{1}{15} - \frac{1}{20} . \\ b = (\frac{4 - 3}{60} ). \\ b = \frac{1}{60} days = 60days.$

Answer 2

B can done his work in 60 days

Explanation:

Given:

1. A can do a work in 20 days

2. A and B complete a work in 15 days

To find:

The B's work

Solution:

==> Work done by A =  20 days

==> A one day work = $\frac{1}{20}$

==> A = $\frac{1}{20}$ ==>1

==> A and B complete a work in 15 days

==> A+B = 15

==> A and B's one day work =    $\frac{1}{15}$

==> A+B =        $\frac{1}{15}$  ==>2

==> Apply the equation 1 in 2

==> $\frac{1}{20}$ + B = $\frac{1}{15}$  

==>  B = $\frac{1}{15}- \frac{1}{20}$

==> B =  $\frac{20-15}{300}$

==>  B =  $\frac{5}{300}$

==> B =  $\frac{1}{60}$

==>  B's one day work is $\frac{1}{60}$

==> B can be done his work in 60 days

==> To check the answer:

==> A+B =       $\frac{1}{15}$

==> Prove : LHS =RHS

==> $\frac{1}{20} + \frac{1}{60}=\frac{1}{15}$

==> $\frac{(3)1}{(3)20} + \frac{1}{60}=\frac{1}{15}$

==> $\frac{3}{60} + \frac{1}{60}=\frac{1}{15}$

==> $\frac{4}{60} =\frac{1}{15}$

==> $\frac{1}{15} =\frac{1}{15}$

==> Hence proved