Question

Find the greater fraction out of 17/20 and 19/25.Find your answer using two different methods

Answer 1

Question 1 - See the pattern -> difference between the numerator and denominator is 1 in all the options. So go with the option with largest integers (like 1/2 is always smaller than 2/3). Clearly the last option

Question 2 - Here the difference between numerator and denominator is not equal in all options

Use this method -> cross multiply the options. Lets take 3/8 on left side and 5/7 on right side (3/8 = 5/7). This will give 21 on left side 40 on right side (21 = 40). Option with greater number will always be greater, so in this case 5/7 is greater than 3/8. You can check all option this way.

I dont think GMAT ever gives large fractions without common difference between numerator and denominator.

Both the methods are full proof and can never go wrong.

Answer 2

$\bold{17/20}$

1st method :

in this method, we shall transform these into decimals and then choose the greater one.

17/20 = 0.85
19/25 = 0.76

from these, it is clear that 17/20 is greater.

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2nd method:

In this method, we will perform cross multiplication and then find the greater one.

we have:

(17x25) and (20 x 19)

➡ 425 and 380

Also, from these, 17/25 is greater.