rate work problem

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by killer1387 » Mon Mar 05, 2012 9:31 pm
gopinathhyd wrote:Machines A, B, and C all three together complete work in 1 hr. Rate of B = 2A, and Rate of c = 3A, how much time will machine A will take to complete the work alone.
m getting 6 hrs.

i.e. rate A=a
hence a+2a+3a=1
a=1/6
time taken=6 hrs

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by GMATGuruNY » Tue Mar 06, 2012 3:57 am
gopinathhyd wrote:Machines A, B, and C all three together complete work in 1 hr. Rate of B = 2A, and Rate of c = 3A, how much time will machine A will take to complete the work alone.
Let the rate for A = 1 unit per hour.
Then the rate for B = 2A = 2 units per hour.
The rate for C = 3A = 3 units per hour.
In 1 hour, the number of units produced by A+B+C = 1+2+3 = 6 units.
Time for A alone to produce 6 units = w/r = 6/1 = 6 hours.
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