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# In a class, 50% of the students studied Mathematics and 40% studied

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Director
Joined: 18 Feb 2019
Posts: 582
Location: India
GMAT 1: 460 Q42 V13
GPA: 3.6
In a class, 50% of the students studied Mathematics and 40% studied  [#permalink]

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30 Mar 2019, 05:39
1
00:00

Difficulty:

5% (low)

Question Stats:

97% (01:22) correct 3% (01:02) wrong based on 33 sessions

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In a class, 50% of the students studied Mathematics and 40% studied Biology. If 20% of the students studied neither Mathematics nor Biology, what percentage of the students studied both Mathematics and Biology?

A. 0%
B. 10%
C. 20%
D. 30%
E. 40%
Manager
Joined: 07 Aug 2017
Posts: 86
Location: India
GPA: 4
WE: Information Technology (Consulting)
Re: In a class, 50% of the students studied Mathematics and 40% studied  [#permalink]

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30 Mar 2019, 07:22
Consider there are 100 students in class. 20 students studied neither Biology nor Mathematics. Therefore, 80 students studied either Biology or Mathematics, that is, B U M = 80. It is given that B = 40 and M = 50.

$$B\cup M = B + M - B\cap M$$
$$80=40+50-B\cap M$$
$$B\cap M = 10$$

-----------------------------------------
Intern
Joined: 25 Nov 2018
Posts: 5
Re: In a class, 50% of the students studied Mathematics and 40% studied  [#permalink]

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02 Apr 2019, 01:16
As it is in percentage , take total students as 100.
Given: 50% studied Maths. ie: 50 students
40% studied Biology ie: 40 students
20% studied none of them.
we have a formula : AUB = A+B+neither -A∩B
Substitute the values in forrmula.
100= 50+40+20-A∩B
A∩B =10

Hope it helps..!
Re: In a class, 50% of the students studied Mathematics and 40% studied   [#permalink] 02 Apr 2019, 01:16
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