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by chaitanya.mehrotra » Thu Jul 28, 2011 7:29 am
4 sewing machines can sew shirts in the ratio 1 : 2 : 3 : 5. The fastest can sew a shirt
in 2 hours. However, the fastest machine breaks. How long will it take the other
three machines to sew a total of 3 shirts?
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Source: — Problem Solving |

by ColumbiaVC » Thu Jul 28, 2011 4:01 pm
(fastest)1:2:3:5(slowest)
=> 2:4:6:10 (hours to sew 1 shirt)

So, combined rate of the rest of the 3 machines to sew 1 shirt is (1/r)=(1/4)+(1/6)+(1/10)
=> (1/r)=(31/60)
=> r=(60/31) hours to sew 1 shirt
for 3 shirts = 3*(60/31)=6hrs(approximately)
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