melguy wrote:

Hello

I am a newbie brushing up my basics on Quant. Please help. I am a bit confused with the method the bench mark values used by MGMAT guide 2. In the problem set Chapter 2 Q10

Put these fractions from the least to the greatest

9/17 , 3/6, 19/20 , 7/15

Explanation

9/17 is slightly more than 1/2

3/16 is slightly less than 1/4

19/20 is slightly less than 1

7/15 is slightly less than 1/2.

I am a bit confused with the language. For example how is 3/16 is slightly less than 1/4.

3 x 5 = 15

3 x 6 = 18

so it should fall between 1/5 and 1/6 hence it should be more than 1/4 not less (if i make any sense!)

Same with all the fractions. The language is exactly opposite what i expected it to be.

Please help clarify.

Another approach can be:

9/17 , 3/6, 19/20 , 7/15

Separate 3/6, 19/20 , 7/15 from 9/17

We see that 60 is the lcm for 6,20,15.

3/6, 19/20 , 7/15

Numerators will be: 30, 57, 28

Thus, 7/15 is the least among 3/6,19/20,7/15.

Now;

compare 9/17 with 7/15

7/15(less than 7/14=1/2) is less than 9/17(more than 9/18=1/2) and least among the choices.

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7/14=1/2

If the numerator(7) is kept constant:

Increase in denominator will decrease the value of the fraction.

Decrease in denominator will increase the value of the fraction.

If the denominator(14) is kept constant:

Increase in numerator will increase the value of the fraction.

Decrease in numerator will decrease the value of the fraction.

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_________________

~fluke

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