Question

A and B alone can do a work in 20 days and 30 days respectively they worked together for some time after that b left if a does the remaining work in 10 days then for how many days b worked?​

Answer 1

A completed a work in 20 days

And B completed that work in 30 days

Hence, when they worked together then after some time B left.

So A do that work 20+10=30

And B before left he do work only 20 days. Hence B work 20 day.

Answer 2

Answer:

ANSWER is 6 days.......

Step-by-step explanation:

In 1day A can do=(1/20) part of the work

In 1day B can do=(1/30) part of the work

In 1day (A+B) can do

=[(1/20)+(1/30)] part of the work

=(5/60)

=(1/12)

Let they togetherly worked for x days...

Then wokdone by (A+B) in x days=(x/12)

Now, wokdone by A in 10 days=(10/20)=1/2

Now,

total work=1

(x/12)+(1/2)=1

x+6=12

x=6

i.e., B worked for 6 days

Hope you have understood.....................