Question

A can build a wall in 30 days , while B alone can build it in 40 days.if they build it together and get a payment of Rs.7000,what is B's share?

Answer 1

Given: If A=30 days
Then, b= 40 days
Therefore, A:B= 40:30= 4:3

A+B= 7000
= 4x+3x=7000
=7x=7000
Therefore x=7000/7=₹1000

If x=₹1000, then
A’s share=3x=3*1000=₹3000
B’s share=4x=4*1000=₹4000
Total= 4000+3000=₹7000

Hope this helps!

Answer 2

A can build a wall 30 days , while B alone can build it in 40 days. If they build it together and get a payment of Rs. 7000.

We have to find B's share.

we know, “efficiency of a man is inversely proportional to number of days taken by him to do a piece of work.”

∵ time taken by A to complete the work = 30 days

time taken by B to complete the same work = 40 days.

∴ ratio of time taken by A to B = 3 : 4.

∴ ratio of efficiencies of A to B = 1/3 : 1/4 = 4 : 3

it means, if A does 4 units , B does just 3 units.

so the ratio of their payment would be = 4 : 3.

let the proportionality constant is x

so, A's share = 4x

B's share = 3x

but total payment is paid to them = 7000

⇒4x + 3x = 7000

⇒x = 1000

so the A's share = 4x = 4 × 1000 = Rs. 4000

B's share = 3x = 3 × 1000 = Rs. 3000

Therefore B's share is Rs. 3000