Question

A and B separately do a work in 10 and 15 days respectively. They worked together for
some days and then A completed the remaining work in 5 days. For how many days
had A and B worked together?​

Answer 1

Step-by-step explanation:

Given

A can do work in 10 days => work done in 1 day is W / 10

Let W be the total work

B can do work in 15 days => work done in 1 day is W / 15

Let n be the number of days they both work together

work done by together in a day = W / 10  + W / 15  = W / 6

=>   n  *  W / 6 + 5 * W / 10  = W

=> n * W / 6 = W/2

=> n =3

hence the number of days they worked together is 3 days