Strategy Guide 3 (5th Ed) - Weighted average

[Harshayes]

Hi there,

I have a basic question since I want to understand this correctly.

This is regarding the weighted average example in 5th edition of strategy guide 3 on pages 56-57. Can someone please clarify how 22.5 and 28 are derived ? And what are these values? What does "Simply write the ratio as fraction, and use the Nr and Dr as weights" mean?

Appreciate the help.

Thanks.

[tim]

Please note that the forum rules indicate you need to include the full text of the problem before we can discuss it, so that other students can benefit from the discussion as well.

[RonPurewal]

More importantly, this is the wrong folder for this question.

This folder is for problems from the GMAT PREP free software only.
Strategy guide questions belong in the MGMAT non-CAT folder.

Please re-post your question there, this time following the forum rules (= post the full text of the question as originally published, along with the answer choices if there are any).
And, please read the forum rules—top post in every folder—if you haven't already.

Thanks.