Question:
Arun scored 36 marks in English, 44 marks in Hindi, 75 marks in mathematics and x marks in science. If he has secured an average of 50 marks, find the value of x.
Solution:
Marks scored by Arun in English = 36
Marks scored by Arun in Hindi = 44
Marks scored by Arun in mathematics = 75
Marks scored by Arun in science = x
Average marks = 50
Thus, we have:
Average marks $=\frac{36+44+75+x}{4}$
$\Rightarrow 50=\frac{155+x}{4}$
$\Rightarrow 155+x=200$
$\Rightarrow x=200-155=45$
$\therefore$ Marks scored by Arun in science $=45$