BREAKING: Target Test Prep releases Brand New 2026 On Demand GMAT prep course

Redeem

gallon and miles

This topic has expert replies
Post new topic Post Reply
Previous Topic Next Topic
Master | Next Rank: 500 Posts
Posts: 345
Joined: Wed Mar 18, 2009 6:53 pm
Location: Sao Paulo-Brazil
Thanked: 12 times
GMAT Score:660

gallon and miles

by shibal » Tue Jun 30, 2009 6:19 pm
At 50 mph a car uses 1 gallon for every 30 miles. If the car starts with a full tank of 12 gallons and drives for 5 hrs at 50mph, the amount of gas used would be what fraction of the tank?

oa: [spoiler]25/36[/spoiler]
Top
Source: — Problem Solving |
Master | Next Rank: 500 Posts
Posts: 392
Joined: Thu Jan 15, 2009 12:52 pm
Location: New Jersey
Thanked: 76 times

by truplayer256 » Tue Jun 30, 2009 6:27 pm
Pretty straightforward question.

Car uses 1 gallon for every 30 miles. It went 5 hours at 50 m.p.h, so it went a total of 250 miles. It used a total of 250/30 or 25/3 gallons. If a full tank is 12 gallons, then the amount of gas used would be 25/3/(12) or 25/36 of the tank.
Top
User avatar
Master | Next Rank: 500 Posts
Posts: 472
Joined: Sun Mar 29, 2009 6:54 pm
Thanked: 56 times

Re: gallon and miles

by ssmiles08 » Tue Jun 30, 2009 7:04 pm
shibal wrote:At 50 mph a car uses 1 gallon for every 30 miles. If the car starts with a full tank of 12 gallons and drives for 5 hrs at 50mph, the amount of gas used would be what fraction of the tank?

oa: [spoiler]25/36[/spoiler]
Think of this question as a manipulation of units. Otherwise it is a direct rate/distance question.

5hrs*(50miles)/hr = 250 miles.

now you know the rate of gallons vs miles = 30 miles/gallon.

we want our end result to be in gallons.

so 250miles/(30m/g) = (25/3) gallons.

now they are asking you the fraction of 12 gallon tank used. both units are in gallons.

so (25/3)/12 = 25/36.
Top
Post new topic Post Reply
• Page 1 of 1