Math Is Fun Forum

aube0008

Member

Registered: 2008-07-01

Posts: 4

Rate Combination problem

I need to know what type of formula or process to use in solving the problem below and other problems like it:

Jonathan can type a 20-page document in 40 minutes, Susan can type it in 30 minutes, and Jack can type it in 24 minutes.  Working together, how much time will it take them to type the same document?

Thanks!

JaneFairfax

Member

Registered: 2007-02-23

Posts: 6,868

Re: Rate Combination problem

integer

Member

Registered: 2008-02-21

Posts: 79

Re: Rate Combination problem

That's assuming that Jack & Susan can type on the same page at the same time.

ZHero

Real Member

Registered: 2008-06-08

Posts: 1,889

Re: Rate Combination problem

Mmmm.. Not exactly 'integer'!
Divide the work in the ratios of the amount of work each one does!
That is 3 : 4 : 5!

So.. Jonathan types 5 pages, Susan types 6.666 pages out of the remaining 15 pages and Jack types the remaining 8.333 pages..
You see, they can work simultaneously but on different parts of the same work and will all finish right after 10 minutes together!:cool:

Last edited by ZHero (2008-07-02 04:06:15)

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