Math, asked by drakeshranjan4575, 1 year ago

A can make a wall in 20 days,b can destroy that wall in 30 days.if a and b working in alternate day then after how many days wall will be complete?

Answers

Answered by Anonymous
13
Sol.
 A can build 1/20 th of the wall in 1 day.
Where as B will destroy 1/30 th of the wall in 1 day and
since they are working on alternate days,
 So in 2 days, 1/20-1/30 = 1/60 th of the wall will be constructed.
So, in 57 × 2 = 114 days, 60 57 th of the work will be completed
and on the 115th day, A will come and completes the remaining 3/60=1/20th of the work.
So it takes 115 days to construct the wall. it is t


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