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

Redeem

Weighted Averages

Expert replies
by topspin20 » Wed Jul 31, 2013 4:36 pm
Hi all,

I am struggling a little bit with the concept of weighted averages.

A certain stationary store sells pencils for $2 and pens for $3. If the average price of pens and pencils sold in a certain day is $2.60, how many pens were sold?

To get the exact number of pens sold, you would need to know the total number of pens and pencils sold, correct?

But how do you determine the ratio of pens to pencils sold with only the above information?

Thank you!
Join the discussion
Source: — Problem Solving |

by luckypiscian » Wed Jul 31, 2013 10:42 pm
Questions seems to be incomplete

but we can surely determine the ratio here
suppose
no. of pencils sold = x
no. of pens sold = y
equate the average now
(2x + 3y)/(x+y) = 2.6
=> 2x + 3y = 2.6x + 2.6y
=> .4y = .6x
=> x/y = 2/3
Join the discussion

by Jim@StratusPrep » Thu Aug 01, 2013 6:32 am
Yes, you only know the ratio (as calculated above) to get the number you would need more information.
GMAT Answers provides a world class adaptive learning platform.
-- Push button course navigation to simplify planning
-- Daily assignments to fit your exam timeline
-- Organized review that is tailored based on your abiility
-- 1,000s of unique GMAT questions
-- 100s of handwritten 'digital flip books' for OG questions
-- 100% Free Trial and less than $20 per month after.
-- Free GMAT Quantitative Review

Image
Join the discussion

by topspin20 » Thu Aug 01, 2013 4:12 pm
Great-thank you for the responses. I was not sure how to calculate the ratio from the information given.
Join the discussion