GMAT Prep Question Flour to Sugar

This topic has expert replies
Junior | Next Rank: 30 Posts
Posts: 26
Joined: Thu Jan 15, 2009 10:25 am

GMAT Prep Question Flour to Sugar

by Nole23 » Sun Jun 21, 2009 6:33 am
What is the ratio of the number of cups of flour to the number of cups of sugar required in a certain cake recipe?

1. The number of cups of flour required in the recipe is 250 percent of the number of cups of sugar required in the recipe.

2. 1 1/2 more cups of flor than cups of sugar are required in the recipe.

OA:A

I understand why 1 is sufficient, but I'm confused as to why 2 is not. Any help would be great.
Source: — Data Sufficiency |

User avatar
Legendary Member
Posts: 519
Joined: Sat Jan 27, 2007 7:56 am
Location: India
Thanked: 31 times

by Neo2000 » Sun Jun 21, 2009 7:39 am
One is expressed as a percentage, the other as a number.

Lets consider 1. If Sugar requires X cups, then flour requires 1.5X cups. A ratio can be computed for this.

Consider 2. If Sugar requires Y cups, then required flour is Y + 1.5 You cannot calculate a ratio for this without knowing the value of Y. From the first statement, you dont necessarily need to the know the value to calculate the ratio.

Master | Next Rank: 500 Posts
Posts: 447
Joined: Sun Apr 19, 2009 9:08 pm
Location: Kolkata,India
Thanked: 7 times
GMAT Score:670

by uptowngirl92 » Fri Aug 21, 2009 4:49 pm
f = s + s(1 1/2) = s + (3*s)/2 = (5*s)/2 ------ f/s = 5/2 ---- Suff..

Guys whats the issue here?Why is this wrong??Please explain.

Junior | Next Rank: 30 Posts
Posts: 15
Joined: Sun Aug 23, 2009 6:58 am
Thanked: 1 times
GMAT Score:770

by gmatcoach » Mon Aug 24, 2009 10:13 am
uptowngirl92

Notice that stmt 2 says 1.5 more cups of flour.

So correcting the bold part of the equation:
f = s + s(1 1/2) = s + (3*s)/2 = (5*s)/2 ------ f/s = 5/2 ---- Suff..

to:
f = s+1.5.

If s = 5, f = 7.5, ratio is 7.5:5 = 3:2
If s = 1, f = 2.5, ratio is 2.5:1 = 5:1

So stmt is ambiguous, hence insufficient.

Senior | Next Rank: 100 Posts
Posts: 85
Joined: Wed Aug 13, 2008 2:21 am
Thanked: 1 times

Re: GMAT Prep Question Flour to Sugar

by sudi760mba » Tue Aug 25, 2009 4:27 am
Let's say
1)
x = sugar
5/2x = flour
5/2:1 establishes the ratio. This is sufficient.

2) x=sugar
x + 3/2 = flour
x=1 and then flour could be 5/2 or
x=2 and then flour could be 7/2..Since this variable, this is not sufficient.

Hence the answer A.

Nole23 wrote:What is the ratio of the number of cups of flour to the number of cups of sugar required in a certain cake recipe?

1. The number of cups of flour required in the recipe is 250 percent of the number of cups of sugar required in the recipe.

2. 1 1/2 more cups of flor than cups of sugar are required in the recipe.

OA:A

I understand why 1 is sufficient, but I'm confused as to why 2 is not. Any help would be great.