Question

There are 200 questions in a three-hour exam. 50 of the 200 questions are of Mathematics. 100 questions are of general knowledge and 50 questions are of science. He took twice as much time on each mathematics question than every other question. So how many minutes did he spend on maths questions?
A) 36 minutes
B) 72 minutes
C) 100 minutes
D) 60 minutes​

Answer 1

Answer:

Let the time taken in each question be n.

$\underline{\bigstar\:\:\textsf{According to the Question :}}$

$\dashrightarrow\tt\:\:Maths + GK + Science = 3\:Hours\\\\\\\dashrightarrow\tt\:\:(50\times2n)+(100\times n)+(50\times n) = 3\:Hours\\\\\\\dashrightarrow\tt\:\:100n + 100n + 50n = 3\:Hours\\\\{\scriptsize\qquad\bf{\dag}\:\:\textsf{Changing Time into Minutes}}\\\\\dashrightarrow\tt\:\:250n = (3\times60)\:minutes\\\\\\\dashrightarrow\tt\:\:250n =180\:minutes\\\\\\\dashrightarrow\:\:\underline{\boxed{\tt n=\dfrac{180\:minutes}{250}}}$

$\rule{150}{1}$

$:\implies\sf \textbf{Time for 1 Question} = \sf\dfrac{180\:minutes}{250}\\\\:\implies\sf \textbf{Time for 50 Question} = \sf\dfrac{180\:minutes}{250}\times 50\\\\\sf{\qquad \qquad \qquad \qquad \qquad\qquad\qquad\! =\dfrac{180\:minutes}{5}}\\\\\textsf{\qquad \qquad \qquad\qquad \qquad\!\qquad\qquad \textbf{= 36 minutes}}$

⠀

$\therefore\:\underline{\textsf{He will take A) \textbf{36 minutes} in Maths Question}}.$

Answer 2

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$\huge\tt{GIVEN:}$

There are 200 questions in a three hour exam

50 questions are of mathematics

100 questions are of general knowledge

50 are of science

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$\huge\tt{TO~FIND:}$

time taken by solving mathematics questions

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$\huge\tt{SOLUTION:}$

Let the time taken per one question be x

⟹Mathematics + General Knowledge + Science = 3 Hours or 180 minutes

⟹(50×2x)+(100×x)+(50×x) = 180 minutes

⟹100x +100x +50x = 180 minutes

⟹250x= 180 minutes

⟹x = 180/250 minutes

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➠Time for 1 question = 180/250 minutes

➠Time for 50 questions = 180/250×50

➠Time for 50 questions = 0.72×50

➠Time for 50 questions = 36 minutes

$\tt{Option~(A)36~Minutes~Is~Correct!}$

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