Question

Rahul obtained 20 and 25 marks in first two tests. Find the minimum marks he should get in the third test to have an average of at least 30 marks.

(a) 60

(b) 35

(c) 180

(d) 45

This question was addressed to me during a job interview.

I would like to ask this question from Algebraic Solutions of Linear Inequalities in One Variable and their Graphical Representation in division Linear Inequalities of Mathematics – Class 11

Answer 1

Right answer is (d) 45

Explanation: Average is at least 30 marks.

Let x be the marks in 3^rd test.

Average = (20+25+x)/3 ≥30

=>45+x≥90 => x≥90-45 => x≥45.

Minimum marks in 3^rd test should be 45.