Question

Mala and Bino can reap a field in 25 days. Mala alone can reap 1/3 of the field in 15 days. How many days Bino alone can reap the field?

Answer 1

Answer : $\bold{56.25 \: days}$



$\bold{Explanation :}$


Given :

Mala and Bino can reap in 25 days

Mala alone can reap 1/3 the field in 15 days


$15 \: days = \dfrac{1}{3} \: work$


$1 \: day = \dfrac{1}{3} \times \dfrac{1}{15}$


$1 \: day \: = \dfrac{1}{45} \: work$


Hence : Mala alone can do 1/45 work in 1 day .


Given :

Mala and Bino work together in 25 days

Work done by both of them in one day = 1/25

We know that work done by Mala in 1 day = 1/45


Let the work done by Bino in 1 day = 1/y


$\dfrac{1}{45} + \dfrac{1}{y} = \dfrac{1}{25}$



$\dfrac{1}{y} = \dfrac{1}{25} - \dfrac{1}{45}$

LCM of 25 and 45 is 225


$\dfrac{1}{y} = \dfrac{9 - 5}{225}$


$\dfrac{1}{y} = \dfrac{4}{225}$



$y = \dfrac{225}{4} = 56.25$


Hence:

Bino alone can reap the field in 56.25 days