The average of 30 numbers is 36. If Z is subtracted from each of these 30 numbers, then the average becomes 28. What is the value of Z?
Show answer & explanation
Correct answer: B
Explanation
The correct answer is Option 2 i.e. 8.
According to the question;
⇒ 30 × 36 - 30Z = 28 × 30
Dividing the above equation by 30, we get
⇒ 36 - Z = 28
⇒ Z = 36 - 28
⇒ Z = 8