Math Is Fun Forum

Neha

Member

Registered: 2006-10-11

Posts: 173

fred/barney

fred can complete 5 jobs in 4 hours
when barney helps him, they can complete 9 jobs in 6 hours
how long would it take barney to complete 1 job

ok i think this is wrong but you tell me :

9/6 = 1/x
9x = 6
x = 6/9
x = 2/3
x = 0.6

help

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MathsIsFun

Administrator

Registered: 2005-01-21

Posts: 7,713

Re: fred/barney

fred = 5/4 jobs/hr
fred + barney = 9/6 jobs/hour

so

barney = 9/6 - 5/4 = 6/4 - 5/4 = 1/4 jobs/hr

So barney would take 4 hours to complete a job. Sack him.

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"The physicists defer only to mathematicians, and the mathematicians defer only to God ..."  - Leon M. Lederman