Question

A can do a piece of work in 20 days and B in 30 days.they began to work together but A left after some days B finished the remaining work in 10 days after how many days did A leave

Answer 1

Answer:

Step-by-step explanation:

A can do a work in 20 days.

A's 1 day work =1/20

B cn do a work in 30 days.

B's 1 day work=1/30

(A+B)'s 1 day work=1/20+1/30

                              =(30+20)/60

                              =50/60=5/6.

Let A worked with B for x number of days.

          (A+B)'S x days work=5x/6

           Remaining work=1-5x/6=(6-5x)/6

B can do 1/30 part of the work in 1 days

B can do whole part of the work in 30 days

B can do (6-5x)/6part of the work in 30×(6-5x)/6 days=5(6-5x)days

Given that B has completed the remaining in 10 days.

∴ 10=5(6-5x)

⇒10/5=6-5x

⇒2-6= -5x

⇒-4=-5x

⇒x=5/4

∴A left after 5/4 days.