Questions about the world of GRE Math from other sources and general math related questions.
manigandaraja100
Students
 
Posts: 2
Joined: Sun Oct 14, 2012 7:12 pm
 

ratios and proportions

by manigandaraja100 Wed Jun 12, 2013 11:02 pm

If 500 pounds of mush will feed 20 pigs for a week,for how many days will 200 pounds of mush feed 14 pigs ?
thomasjohnonline
Students
 
Posts: 1
Joined: Thu Jun 13, 2013 10:24 pm
 

Re: ratios and proportions

by thomasjohnonline Sun Jun 16, 2013 6:28 am

4 days

Mush needed for 1 pig for 1 day = 500/(20*7)
No. of days for 14 pigs will go on 200 pounds of mush = 200*7/14*25 = 4
tommywallach
Manhattan Prep Staff
 
Posts: 1917
Joined: Thu Mar 31, 2011 11:18 am
 

Re: ratios and proportions

by tommywallach Wed Jun 19, 2013 8:39 am

Hey Guys,

This isn't a ratios and proportions question. It's a work question.

Rate * Time * # of Workers = Work

Rate * 7 * 20 = 500
rate = 50/14 = 25/7

Now apply that to the second situation:

25/7 * Time * 14 = 200
50 * Time = 200
Time = 4 days

Always important to know what time of question you're tackling, because it informs what technique you use. You wouldn't think of using the rate equation if you didn't know it was a rate question!

-t