Comparing fractions

[beater]

Which of the following is greater than 2/3?

a. 33/50
b. 8/11
c. 3/5
d. 13/27
e. 5/8

Could you please explain an easy and time efficient way to solve such problems that requires comparing fractions. Thanks!

[cramya]

In this case take 2/3 and cmpare it to each fraction

The comparison can be made easier if you make the denominators the same (LCM) for th2 fractions in question

Eg: 2/3 and 33/50

2/3 = 100/150

33/50 = 99/150 Rule out A)

2/3 and 8/11

2/3 = 22/33 and 8/11 is 24/33 This is the answer(B) in this situation and look no further since only 1 answer is right on GMAT.

[cramya]

look no further since only 1 answer is right on GMAT

Dont want to lisalead anyone wiht the above statement of mine

Clarification: For this question there cant be 2 fractions greater than 2/3 because that would be ambigous in terms of the choices we could pick.

For questions like

I) and II) are true
Only I) is true
I),II,II) are true

you would have to evalauate each choice to confirm your selection or elimination

Hope this helps!

[Ian Stewart]

Which of the following is greater than 2/3?

a. 33/50
b. 8/11
c. 3/5
d. 13/27
e. 5/8

Could you please explain an easy and time efficient way to solve such problems that requires comparing fractions. Thanks!

There are a few techniques that can be used to compare fractions, but in this case, the fractions are relatively easy to work with:

33/50 = 66/100 = 0.66
3/5 = 6/10 = 0.6
13/27 is less than 13/26, so is less than 1/2 = 0.5
5/8 = 4/8 + 1/8 = 0.5 + 0.125 = 0.625

More importantly, though:

2/3 = 8/12 which must be less than 8/11, since 8/12 has the larger denominator (and since we're only dealing with positive numbers).

cramya's approach above is also great- there are several ways to look at these kinds of problems.