Question

A can finish a piece of work in 42 days. b is 40% more efficient than
a. b started working alone and after few days a replaced him. if a could finish the remaining work in 7 days, for how many days b worked ?​

Answer 1

Answer:

25 days

Step-by-step explanation:

A take 42 days to complete work

A 1 day work is 1 / 42

A 7 days work 7 / 42 = 1 / 6

remaining work = 1 - 1/ 6 = 5 / 6

B is 40% more efficient than A means B efficiency is 140/ 100 × A efficiency

I.e. If A efficiency is 1

so B efficiency is 140/ 100 = 7 / 5

let B takes x days to complete work

SO 1 × 42 = 7 / 5 × x

x = 30 days

so 1 day work of B is 1 / 30

let B worked for y days

so 1/30 × y = 5/6

y = 25 days