Question

Find the average of all the prime numbers between 60 and 90.

• A. 72
• B. 74.7
• C. 74
• D. 73.6

Hint:

List all primes carefully and then find their average by dividing sum by count.

Answer 1

The Correct Option is B

Prime numbers between 60 and 90 are: 61, 67, 71, 73, 79, 83, 89.
Step 1: Sum all prime numbers:
\[ 61 + 67 + 71 + 73 + 79 + 83 + 89 = 523 \] Step 2: Count the numbers: 7 primes.
Step 3: Calculate the average:
\[ \frac{523}{7} \approx 74.7 \] Hence, the average is \(\boxed{74.7}\).