Difficult Math Question #34 - Arithmetic

[800guy]

Two numbers are less than a third number by 30% and 37 % respectively. How much percent is the second number less than the first?

a) 10 % b) 7 % c) 4 % d) 3 %

[ajith]

Two numbers are less than a third number by 30% and 37 % respectively. How much percent is the second number less than the first?

a) 10 % b) 7 % c) 4 % d) 3 %

A is the answer ..

say the original no is X
first no: is .7X
second no: is .63X

it is (.7-.63) X/.7 =.1 =10%

[rajs.kumar]

agree with ajith.

[800guy]

here's the OA:

.7 & .63

diff in %= (.7 - .63)/.7 * 100= .07/.7 * 100= 10%

[navdeepbajwa]

I can't understand this part

diff in %= (.7 - .63)/.7 * 100

why we have to divide by 0.7 why can't it be difference * 100 = 7%

thanks

[regor60]

I can't understand this part

diff in %= (.7 - .63)/.7 * 100

why we have to divide by 0.7 why can't it be difference * 100 = 7%

thanks

Keep track of the base.

The difference of 7% is referenced to the "third" number. 10% is the difference referenced to the "first" number, which itself is 70% of the "third" number. The question is asking for the difference referenced to the "first" number.