Posted by **clara** on Thursday, January 5, 2012 at 5:45am.

lean can paint her new apartment 3 hours longer than his friend,carlos.if both can do painting in 2 hours,how long will it take each one to finish the job alone?

- algebra -
**Bayarbold**, Thursday, January 5, 2012 at 6:42am
labour*time=job time=job/labour

time=3 and 3x=1 x=1/3

If both can do painting in 2 hours,So

(x+y)2=1 x=1/3 hence (1/3+y)*2=1

And y is 1/6.We can say that it take 6hours to finish the job alone.

- algebra -
**Reiny**, Thursday, January 5, 2012 at 8:26am
let Carlos' time be x hrs

so rate for Carlos = 1/x

Lean's time is x+3

Lean's rate = 1/(x+3)

combined rate = 1/x + 1/(x+3)

= (x+3 + x)/(x(x+3)) = (2x+3)/(x(x+3))

1/[ (2x+3)/(x(x+3))] = 2

x(x+3)/(2x+3) = 2

x^2 + 3x = 4x + 6

x^2 - x - 6 = 0

(x-3)(x+2) = 0

x = 3 or x=-2, the latter is not possible

Carlos would take 3 hrs, and Lean would take 6 hrs alone

check:

combined rate = 1/3 + 1/6 = 1/2

combined time = 1/(1/2) = 2

- algebra -
**Sharon**, Saturday, January 21, 2012 at 1:46pm
Keiko bicycles 4km/h faster than Carlos. In the same time it takes Carlos to Bicycle 45km, Keiko can bicycle 57km. How fast does each bicyclist travel?

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