Rohan scored 70 and 75 marks in the first two tests. How many marks should he score in the third test to get an average of 70 marks?
Show answer & explanation
Correct answer: D
Explanation
The correct answer is Option 4 i.e. 65.
We know that,
Average = Sum of observations/Number of observations
Let the marks scored in the third test be x
Sum of the marks in three subjects = Average × Number of tests
⇒ (70 + 75 + x) = 70 × 3
⇒ 145 + x = 210
⇒ x = 210 - 145
⇒ x = 65
Hence, the mark to be obtained in the third test is 65.