Question

A does 80% of work in 20 days , he then calls b and they together finish remaining work in 3 days how long b alone can do the work

Answer 1

37 1/2 days taken by B to complete work alone

Answer 2

Answer:

B can complete the work in 37.5 days

Step-by-step explanation:

We are given that A does 80% of work in 20 days

Work done by A in 20 days =$\frac{80}{100}=\frac{4}{5}$

Work done by A in 1 day = $\frac{\frac{4}{5}}{20}=\frac{1}{25}$

Since 80% is work done .

So, Remianing 20% work is done in 3 days

Work done by A and B in 3 days$\frac{20}{100}=\frac{1}{5}$

Work done by A and B in 1 day =$\frac{\frac{1}{5}}{3}$

                                                   =$\frac{1}{15}$

Work done by B in 1 day = $\frac{1}{15}-\frac{1}{25}=\frac{2}{75}$

B can complete work in $\frac{75}{2}$

=> B can complete the work in 75/2 days = 37.5 days

Hence B can complete the work in 37.5 days