smartyman wrote:
If 6 men can do a piece of work in 30 days of 9 hours each, how many men will it take to do 10 times the amount of work if they work for 25 days of 8 hours?
A. 61
B. 64
C. 84
D. 81
E. 94
Please help explains using rates formulae as I could not get the answer. Thanks
One version of the rate formula approach . . .
Use standard W = RT formula, but add (# of workers or machines) to R*T, thus: W =
#*R*T
Work = (# of workers) * individual rate * timeScenario 1Get individual rate from first scenario, where t = (30 * 9hrs = 270 hrs)
Work = # * r * t1 = 6 *
?? * 270
1 =
r * 1620
r =
\(\frac{1}{1620}\)Scenario 2At that rate, how many men will it take to do 10 times the amount of work if they work for 25 days of 8 hours?
t = (25 * 8 hrs = 200 hrs)
Work = # * r * t 10 =
?? *
\(\frac{1}{1620}\) * 200
10 =
# *
\(\frac{200}{1620}\)# of workers =
\(\frac{10}{(\frac{200}{1620})} =\) # of workers =
\((10 * \frac{1620}{200})=(\frac{1620}{20})=\frac{162}{2}= 81\)Answer D
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