Question

A and B together can finish apiece of work in15 days B alone can finish it in 25 days in how many days can A alone finish the work

Answer 1

A can finish the work in
$37 \times \frac{1}{2} days$

Answer 2

In this type of problems we generally take the reciprocals.
Here
Days require by A + B together = 15, Days require by B = 25 is given.
Using Reciprocal of no. of days by A + Reciprocal of no. of days by B = reciprocal of no. of days by ( A+ B )

A + 1 / 25 = 1/15
A = 1/15 - 1/25
LCM of 15 and 25 is 150
A = 10/150 - 6/150
A = 4 /150
A = 2 / 75
Taking Reciprocal
No.of days require to complete the work alone by 75/2 i.e. 37.5 days