Questions about the world of GMAT Math from other sources and general math related questions.
LGOdream
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Guide 2 v4.2 - page 15 - errata?

by LGOdream Thu Aug 04, 2011 4:18 am

"If x is the decimal 8.1d5, with d as an unknown digit, and x rounded to the nearest tenth is equal to 8.1, which digits could not be the value of d?"

Official answers include 5, 6, 7, 8, 9.

But shouldn't also 4 be included?

8.145 -> 8.15 -> 8.2

The thousandths digit (5) actually rounds up the hundredths digit so only 1, 2, 3 would actually produce a 8.1.
LGOdream
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Re: Guide 2 v4.2 - page 15 - errata?

by LGOdream Tue Aug 09, 2011 12:17 pm

Another one:

Guide 3 v4.2, page 187, exercise 5:

A cyclist travels the length of a bike path that is 225 miles long, rounded to the nearest mile. If the trip took him 5 hours, rounded to the nearest hour, then his average speed must be between:

Solution: If the cyclist rode 225 miles, rounded to the nearest mile, (...), he traveled between 224.5 and 225.5 (...)

Shouldn't it be between 224.5 -> 225 and 225.4 -> 225?

225.5 should be rounded to 226.0 already.

Same goes for hours, 4.5 and 5.5 hours. Shouldn't it be 4.5 to 5.4?
jnelson0612
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Re: Guide 2 v4.2 - page 15 - errata?

by jnelson0612 Wed Aug 17, 2011 6:11 pm

Here's the errata page: http://www.manhattangmat.com/errata.cfm

Neither of these problems is included; they are actually correct as is. Would you please repost in our math strategy guide forum? It is: manhattan-gmat-math-strategy-guides-f7.html That is where they belong, and someone there will help you. Thanks!
Jamie Nelson
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