hi.. my advice to you is remember fractions till 20..!!!vinnaymb wrote:Hi All,
This one stumbled me.
What is 10/22 of 5/18 of 2000?
This is from MGMAT.
how to benchmark the values and how to get the final answer.
Thanks.
benchmarking values - fraction
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manpsingh87
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manpsingh87
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1/4=25%vinnaymb wrote:well...When a fraction appears to be close to two benchmarks (ie. 5/18 is close to both 1/4 and 1/3), how does one choose...
1/3=33.33%
5/18=27% approx.
so out of 1/4 and 1/3 5/18 is closest to 1/4 so i would pick 1/4..!!!
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SarahLiz
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Actually, I approached this differently. What I did was set up the equation:
2000*(5/18)*(10/22)
And reduced the fraction to:
500*(5/9)*(10/11)= 25,000/99
Obviously 99 is close to 100 so 25,000/100 = 250
2000*(5/18)*(10/22)
And reduced the fraction to:
500*(5/9)*(10/11)= 25,000/99
Obviously 99 is close to 100 so 25,000/100 = 250
Test date: 5/18/2011
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Brent@GMATPrepNow
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It would be useful to see the answer choices for this one, since the answer choices will dictate our approach.vinnaymb wrote:Hi All,
This one stumbled me.
What is 10/22 of 5/18 of 2000?
This is from MGMAT.
how to benchmark the values and how to get the final answer.
Thanks.
If the answer choices are sufficiently spread apart, then we can quickly solve the question by estimating.
For example, Since 10/22 is just a little less than 1/2, we know that (10/22)(2000) will be a little less than 1000 (sure, the real product is about 909, but if the answer choices are sufficiently spread apart, then this level of accuracy will be enough to solve the question)
Brent Hanneson - Creator of GMATPrepNow.com
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Stuart@KaplanGMAT
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Hi!vinnaymb wrote:Hi All,
This one stumbled me.
What is 10/22 of 5/18 of 2000?
This is from MGMAT.
how to benchmark the values and how to get the final answer.
Thanks.
First, I wholeheartedly agree with Brent - please provide the answer choices for every question that you post, since many strategic approaches rely on the choices.
Dealing with your specific question, however:
Since we're rounding 10/22 UP to 1/2, I'd round 5/18 DOWN to 1/4 - that way we're more likely to be close to the actual value of the expression.well...When a fraction appears to be close to two benchmarks (ie. 5/18 is close to both 1/4 and 1/3), how does one choose...
To Sarah's point - great decision! The later you leave estimating, the more accurate your estimate will be. Since we see that, in this problem, some of the numerators have factors in common with some of the denominators, it's definitely worth doing some simplification before estimating.
Stuart Kovinsky | Kaplan GMAT Faculty | Toronto
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