Of the 48 students in a class, 16 like to study History. What percenta

Question

Of the 48 students in a class, 16 like to study History. What percentage of the girls in the class do not like to study History?

(1) One-third of the boys in the class like to study History

(2) The number of girls who like History is 50 percent of the number of girls who do not like History

chetan2u · Accepted Answer

A bit confusing question and likely that students go wrong if they miss out crucial information in statement I.

Of the 48 students in a class, 16 like to study History. What percentage of the girls in the class do not like to study History?

(1) One-third of the boys in the class like to study History
  So, we don't have anything about girls, so it should be insufficient  .
But the ratio of all the students who like history, 16/48 or 1/3, being EQUAL to the ratio of boys who like history gives you the answer..
If over all ratio of something in a set and ratio of the same thing in one of the two subsets is same, then the ratio will be same even in second subset.
For example ..
If boys are 12, 1/3 of 12 or 4 boys like history, so remaining 16-4=12 who like history are girls and total girls are 48-12=36, that is 12/36 or 1/3 girl like history.
Similarly let number be 30 boys and 18 girls. 1/3 of 30 or 10 boys like history so remaining 16-10 are girls and as a fraction it is 6/18=1/3.
So our answer is 1-(1/3) or 2/3.
Sufficient

(2) The number of girls who like History is 50 percent of the number of girls who do not like History
Let the number who do not like history be g, then who like history is 0.5g..
As a % g is g/(g+0.5g)=1/1.5=2/3..66.67%
Sufficient

D

madgmat2019 · Answer

Of the 48 students in a class, 16 like to study History. What percentage of the girls in the class do not like to study History?

(1) One-third of the boys in the class like to study History

(2) The number of girls who like History is 50 percent of the number of girls who do not like History

Let the no.of boys be 'b' and no.of girls be 'g'
From give g+b=48
(1) boys who like to study History is 1/3(48)= 16 i.e percentage of the girls in the class do not like to study History = 0 ...Sufficient

(2) The number of girls who like History is 50 percent of the number of girls who do not like History....Sufficient

OA: D

talbanimohit28 · Answer

Hello, Can someone please post a detailed solution to this problem? Thanks.

chetan2u · Answer

Statement I is not correct. 48 is total, and not number of boys alone.

vishumangal · Answer

Could you please elabroate your statement 1, it says that 1/3 of the boys in class like history. According to your calculation you have taken 1/3 of the class... please explain

Posted from my mobile device

talbanimohit28 · Answer

Hi Chetan, Thanks for this post.

"If over all ratio of something in a set and ratio of the same thing in one of the two subsets is same, then the ratio will be same even in second subset."

This line is a bit tricky, but it makes sense the more you think about it.

bumpbot · Answer

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Of the 48 students in a class, 16 like to study History. What percenta

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