The average of 8 consecutive natural numbers is (25/2). These numbers are in ascending order. What is the average of the last three numbers?
Show answer & explanation
Correct answer: C
Explanation
Given:
Number of terms = 8, Average = 25/2
According to the formula:
Average = (First term + Last term) / 2
First term + Last term = 25
Let the first term be 'a'
Then the last term = a + 7
a + (a + 7) = 25
2a + 7 = 25
2a = 18
a = 9
The numbers are: 9 to 16
The last three numbers are: 14, 15, 16
Average = (14 + 15 + 16) / 3 = 45 / 3 = 15