The average of fourteen numbers is 46. The average of first five is 43 and that of last six numbers is 49.5. The sixth and seventh numbers are respectively 4 and 8 greater than the eighth mumber. What is the average of sixth and seventh numbers?
Show answer & explanation
Correct answer: A
Explanation
The correct answer is Option 1 i.e. 46
Total sum = 14 × 46 = 644
First 5 sum = 5 × 43 =215 , last 6 sum = 6 × 49.5 = 297
Let 8th = x, then 6th = x + 4, 7th = x + 8
644 = 215 + (x + 4) + (x + 8) + x + 297
644 = 524 + 3x ⇒ x = 40
6th = 44, 7th = 48
Average = (44 + 48)/2 = 46