Posted by **majumder** on Thursday, April 26, 2012 at 10:20am.

A does 8/15 of a work in 8 days and the remaining work is finished with the assistance of B in 4 days . how long will B take to do the work alone

- math -
**Reiny**, Thursday, April 26, 2012 at 11:36am
A's rate = (8/15)W / 8 = W/15

let B's rate = W/x , where x is the time it would take B to do the job

combined rate = W/15+W/x = (Wx + 15W)/(15x)

then 4(Wx + 15W)/(15x) = (7/15)W

divide by W and expand

(4x + 60)/(15x) = 7/15

times 15

(4x+60)/x = 7

multiply by x

4x + 60 = 7x

x = 20

it would take B 20 days

## Answer this Question

## Related Questions

- MATH - A does 8/15 of a work in 8 days and the remaining work is finished with ...
- math - A does 8/15 of a work in 8 days and the remaining work is finished with ...
- math - A and B together can make a wall in 60 days. A has worked for 12 days, B ...
- time n work - a and b together can do a piece of work in16 days.b and c can do ...
- maths - Please guide me to solve the below problem: 'A'an do 2/3 of a work in 40...
- math - 1.a collection of 105 coins consists of 1 peso and 5 pesos. if the total ...
- Math - 1) 60 meters of fencing are needed to fence in a square lot. What is the ...
- math - A and B can finsih a work in 16 days and 12 days respectively. A started ...
- maths - A and B together can do a piece of work in 12 days; B and C together can...
- maths - A and B together can do a piece of work in 12 days; B and C together can...