Question

Ravi obtained 70 and 75 marks in first two unit test. Find the minimum marks he should get in the third test to have an average of at least 60 marks.

Answer 1

Let x be the marks Ravi obtained in the third unit test.

Since the student should have an average of at least 60 marks,

According to the question,

`(70 + 75 + x)/3 ≥  60`

= `(145 + x)/3  ≥  60`

Multiplying both sides by 3,

145 + x ≥ 180

= x ≥ 180 – 145

= x ≥ 35

Thus, the student must obtain a minimum of 35 marks to have an average of at least 60 marks.