a% of b is increased by a%.

Question

GMATBusters’ Quant Quiz Question -2

a% of b is increased by a%. what is the result in terms of a and b?
A) 100ab+a
B) ab + a/100
C) 100ab + a/100
D) 100ab + ab/100
E) ab(a+100)/10000

GMATBusters · Answer

Official Solution 
a% of b is increased by a%. what is the result in terms of a and b?
a% of b = ab/100
 increasing by a% = multiplying by (1+a/100) 
hence result is ab/100 * (1+a/100)
= ab(a+100)/10000 
E

Raxit85 · Answer

a% of b is increased by a%. what is the result in terms of a and b?
A) 100ab+a
B) ab + a/100
C) 100ab + a/100
D) 100ab + ab/100
E) ab(a+100)/10000

a/100 * b + a/100 * ab/100
ab/100 (1 + a/100)
ab/100 (100+a/100)
ab (100+a)/10000
Imo. Ans. E

akadiyan · Answer

Lets substitute numbers for a and b

Let A = 10 , B = 100

Step 1:
a% of b is increased by a%. Based on our numbers , 10% of 100 is increased by 10%. 10% 100 is 10 which is increased by 10% again. so we have 11.

Step 2:
What is result in terms of a and b.

Basically we need to find "11 is what in terms of 10 and 100". When we substitute each answer option, we get E as the answer.

Ans:   E

TheNightKing · Answer

Let's play with numbers first :
a% of b is increased by a%.

Lets say b is 100. a is 20. So 20% of 100 is 20. Cool.

Increase 20 by 20% we get 24.

Let's go to options.

A) 100ab+a - This value will result in a very high value so clearly not the right choice.
B) ab + a/100 - Same as choice A.
C) 100ab + a/100 - Same as Choice A
D) 100ab + ab/100 - Same as Choice A
E) ab(a+100)/10000 - 
 (100*20(120)/10000) 
 1*2*12 
 24

Answer E.

Approach 2 : Algebra
a% of b = ab/100
Increase by a%. This means take the a% of original number and add the value to it.

(ab/100) + ((a/100) * (ab/100)) 
 (ab/100) + (a*ab/100*100) 
 (ab/100) + (a^2*b/10000) 
 (100ab+a^2*b/10000) 
 (ab(100+a)/10000)

Answer E

yashikaaggarwal · Answer

OA is supposedly B
As A% of B is increased by a%
And B option is the only feasible option defining relationship between a and b

Posted from my mobile device

abannore · Answer

a% of b =  \frac{ab}{100} 
This is increased by a% so final result would be:
 \frac{ab}{100} + \frac{a}{100}*(\frac{ab}{100}) 
=  \frac{100ab+a^2 b}{10000} 
= \frac{ab(100+a)}{10000}

Option E

Kinshook · Answer

Given: a% of b is increased by a%.

Asked: what is the result in terms of a and b?

a% of b = ab/100
ab/100 is increased by a%, the result = ab/100 (1+a/100) = ab(100+a)/10000

A) 100ab+a
B) ab + a/100
C) 100ab + a/100
D) 100ab + ab/100
E) ab(a+100)/10000

IMO E

ashwini2k6jha · Answer

Answer :E

b X a/100(1+a/100)
=ab(100+a)/10000

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a% of b is increased by a%.

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