A sporting goods store ordered an equal number of white and

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BTGmoderatorLU: Moderator; Posts: 2611; Joined: Sun Oct 15, 2017 1:50 pmFollowed by: 6 members

by BTGmoderatorLU » Fri Apr 27, 2018 2:22 pm

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A sporting goods store ordered an equal number of white and yellow tennis balls. The tennis ball company delivered 30 extra white balls, making the ratio of white balls to yellow balls 6:5. How many tennis balls did the store originally order?

A. 120
B. 150
C. 180
D. 300
E. 330

The OA is D.

Please, can anyone assist me with this PS question? I need help to solve it. Thanks!

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Source: Beat The GMAT — Problem Solving | Fri Apr 27, 2018 2:22 pm

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by [email protected] » Fri Apr 27, 2018 5:26 pm

Hi All,

We're told that a sporting goods store ordered an EQUAL number of white and yellow tennis balls, but the tennis ball company delivered 30 extra white balls, making the ratio of white balls to yellow balls 6:5. We're asked for the TOTAL number of tennis balls that the store originally ordered. This question can be solved in number of different ways, including by TESTing THE ANSWERS. Based on the answer choices, since the 30 extra white balls were enough to turn a 5:5 ratio into a 6:5 ratio, we should start with one of larger options. Let's TEST Answer D...

Answer D: 300 balls
IF... there were 300 total tennis balls...
there would be 150 white balls and 150 yellow balls
Adding 30 white balls would give us a ratio of 180:150
180:150 = 18:15 = 6:5
This is an exact match for what we were told, so this MUST be the answer!

Final Answer: D

GMAT assassins aren't born, they're made,
Rich

Contact Rich at [email protected]

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Jeff@TargetTestPrep: GMAT Instructor; Posts: 1462; Joined: Thu Apr 09, 2015 9:34 amFollowed by: 22 members; Location: New York, NY; Thanked: 39 times

by Jeff@TargetTestPrep » Fri May 04, 2018 9:34 am

BTGmoderatorLU wrote:A sporting goods store ordered an equal number of white and yellow tennis balls. The tennis ball company delivered 30 extra white balls, making the ratio of white balls to yellow balls 6:5. How many tennis balls did the store originally order?

A. 120
B. 150
C. 180
D. 300
E. 330

We can let the number of white balls = the number of yellow balls = b; thus:

(b + 30)/b = = 6/5

5(b + 30) = 6b

5b + 150 = 6b

150 = b

The company originally ordered 300 balls.

Answer: D

Jeffrey Miller
Head of GMAT Instruction
[email protected]

See why Target Test Prep is rated 5 out of 5 stars on BEAT the GMAT. Read our reviews

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