Question

Arjun gets 62 marks out of 100 in English, 81 out of 120 in chemistry and 75 out of 150 in maths. Find the average marks of Arjun (in percentage) in all three subjects.

Answer 1

Hint: We first calculate the percentage of the marks obtained by Arjun in each individual subject then we add the percentage of all three subjects and finally we divide the total percentage by the total number of the subjects. In this way we get Arjun average marks in percentage.

Complete step-by-step answer:
we are given that the mark in English obtained by Arjun is 62 out of 100. So now we have to find the percentage of marks obtained for Arjun in English
$\begin{align}
  & =\dfrac{62}{100}\times 100\% \\
 & =62\% \\
\end{align}$
Also we are given that the mark in Chemistry obtained by Arjun is 81 out of 100. So now we have to find the percentage of marks obtained for Arjun in Chemistry
$\begin{align}
  & =\dfrac{81}{120}\times 100\% \\
 & =67.5\% \\
\end{align}$
Similarly we are also given that the mark in Maths obtained by Arjun is 75 out of 100. So now we have to find the percentage of marks obtained for Arjun in Maths
$\begin{align}
  & =\dfrac{75}{150}\times 100\% \\
 & =50\% \\
\end{align}$
Therefore sum of the percentage in all three subject is
$\begin{align}
  & =62\%+67.5\%+50\% \\
 & =179.5\% \\
\end{align}$
Now to find the average percentage of marks obtained in three, we will divide the total percentage by the total number of the subject.
Therefore the total number of the subjects $=3$
So average percentage in all the three subjects is
$\begin{align}
  & =\dfrac{179.5\%}{3} \\
 & =59.83\% \\
\end{align}$
Hence, the average marks of Arjun (in percentage) in all the three subjects $=59.83\%$


Note: Since in the question the percentage depends on the marks obtained out of the total marks of a subject and the average of any quantity is depending on the Sum of the total to the number of quantities. So, if the question provides more subjects, say Physics or Biology then the denominator of the average would also increase to five. Before solving this kind of question, better will be to learn all the formulas as well as its application and then move towards average.