Bunuel wrote:
Seven machines can complete a job in h hours. How long, in terms of h, will it take 5 machines to complete 2 jobs?
A. 5/(14h)
B. 7h/5
C. 14h/5
D. 5h/7
E. (h + 5)/14
For abstract or complicated "# of workers" questions, I use a table, where "# of workers" is the first column before rate, time, work.
It's fast. For me, after having done it a couple of times, it helped me understand the concepts because I wasn't fixated on keeping values straight.
You just add one more variable to the "LHS" of the WR=T equation ... add
# of workers*R*T=W
Then rearrange the equation. This question, per this method, asks first that you find rate, then, with different number of workers and different amount of work, that you find time. See table.
Case 1: Numerator is 1. Denominator is 7*h. Thus we get
RATE 1/7h
Case 2: Numerator is 2. Denominator is 5*(1/7)(h)
Case 2 numerator and denominator ====> 2 ÷ (5/7)h
= 2 x 7h/5
= 14h/5
Attachments
NO. OF WORKERS -W-R-T-TBL.jpg [ 14.76 KiB | Viewed 1594 times ]
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