here's another word prob

[dolor]

I'm just full of 'em...

Bob gave 4/5 of his pencils to Barbara. Then he gave 2/3 of the remaining pencils to Bonnie. If he ended up with 10 pencils, with how many pencils did he start?

[jemidiah]

10 pencils = 1/3 of what he had before he gave some to Bonnie, so he 30 pencils = 1/5 of what he had before he gave some to barbara, meaning he had 150 total.

[DiGiTaIErRoR]

10/x = 1/3

x=30

30/x = 1/5

x=150

[trasogus]

Yeah, everything is correct, I just want to summarize the situation:

x - all pencils that he had

(4/5)x - it's what he gave to furst girl

x - (4/5)x - it what he had left after

[x -( 4/5)x] * (2/3) - is what he gave to second girl

so we'll get:

x - (4/5)x - [x - (4/5)x] * (2/3) = 10
x - (4/5)x - [(2/3)x - (8/15)x] = 10
x - (4/5)x -(2/3)x + (8/15)x = 10
x*(1 - 4/5 - 2/3 + 8/15) = 10
x*(1 - 12/15 - 10/15 + 8/15) = 10
x*(1 - 14/15) = 10
(1/15)x = 10
x = 150


That's maybe a long way, but it generalizes the situation and puts all in perspective where everything is connected to each other.

P.S.
And that’s the only acceptable way in math and programming IMHO