Strategy Guide Question for Guide 2 on Percents

[carolina.huaranca]

For question 18 on page 158 I am unclear how to evaluate the answer choices.

I was able to arrive at the largest allowable of 7 7/8 and see that this is 31.25% above 6 so do I assume that I can't go above 31.25% which is why I have to pick possible increases of C, and D. When I read this I did not see 31.25% and I saw that 30%+ so I got confused.

When I arrive at the smallest allowable area of 4 3/8 should I have set 27.1% as the smallest decrease which is why -30% didn't work?

Any guidance on better understanding this question is appreciated.

[tommywallach]

Dear Carolina,

You have it pretty much down. The largest possible length is 3.5, and largest possible width is 2.25.

Largest possible area = 7.875 (7 and 7/8).

This is 31.25% greater. Remember, the range of the length is EVERYTHING from 3-3.5, and the range of the width is EVERYTHING from 2.25. That means that every area BETWEEN 6 and 7.875 is possible. That means that the increase could be anything from 0% to 31.25% (including both 30% and 25%). Keep in mind, it does NOT say "30% +" as you wrote, which would imply MORE than 30%. It just says "+ 30%", which implies an increase of 30%, which is within the range.

Make sense?

-t