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

Redeem

not so hard, but please explain

This topic has expert replies
Post new topic Post Reply
Previous Topic Next Topic
Junior | Next Rank: 30 Posts
Posts: 17
Joined: Tue Jul 08, 2008 1:29 pm

not so hard, but please explain

by notgoodinmath » Mon Jul 21, 2008 12:15 pm
During a special promotion, a certain filling station is offfering a 10% discount on gas purchased after the first 10 gallons. If kim purchased 20 gallons of gas, and Isabella purchased 25 gallons of gas, then Isabella's total per-gallon discount is what percent of Kim's total per-gallon discount?

a)80%
b)100%
c)116.7%
d)120%
e)140%


thank you!
Top
Source: — Problem Solving |
Legendary Member
Posts: 661
Joined: Tue Jul 08, 2008 12:58 pm
Location: France
Thanked: 48 times

by pepeprepa » Mon Jul 21, 2008 12:26 pm
Not so hard but need method.

1gallon=1€
Kim buys 20 gallons; the discount value is (20-10)*10/100=1€
Isa buys 25 gallons; the discount value is (25-10)*10/100=1,5€

Total amount of discount per-gallon:
Kim: 1/20
Isa: 1,5/25

Kim is the reference for the calculation of the percentage, so we make a cross-calculating operation.
1/20 3/50
100 x


x/20=(3/50)*100
x/20=6
x=120


d)120%
Top
Junior | Next Rank: 30 Posts
Posts: 17
Joined: Tue Jul 08, 2008 1:29 pm

by notgoodinmath » Mon Jul 21, 2008 1:24 pm
what exactly did you do here:
1/20 3/50
100 x

thanks
Top
Legendary Member
Posts: 661
Joined: Tue Jul 08, 2008 12:58 pm
Location: France
Thanked: 48 times

by pepeprepa » Mon Jul 21, 2008 1:33 pm
I just write it like that on my paper, but it is that:

(1/20)/100=(3/50)/x
Top
Post new topic Post Reply
• Page 1 of 1