Question

The average (mean) of 90 numbers is 60, and the average of 60 numbers is 90. What is the average of all the numbers?

a. 75
b. 80
c. 85
d. 90

Answer 1

The average of all the numbers would be 144.

Step-by-step explanation:

To find the average of all the numbers, we need to know the total sum of the numbers. Let's assume there are 100 numbers in total. The sum of these 100 numbers can be calculated by multiplying the average of the first 90 numbers (60) by 90 and the average of the next 60 numbers (90) by 60. The sum of the 100 numbers would then be 90 * 60 + 60 * 90 = 9000 + 5400 = 14400. Hence, the average of all the numbers would be 14400 divided by 100, which is equal to 144. Therefore, the correct answer is not listed among the options provided.