benchmarking values - fraction

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.

hi.. my advice to you is remember fractions till 20..!!!

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...

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...

1/4=25%
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..!!!

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

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.

Hi!

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:

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...

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.

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.

Picked it up from MGMAT they have not given any choice answers for this question.