A list of 15 numbers has an average of 339. When two numbers are deleted from the list, the average of the remaining numbers is 318.
- What is the sum of 15 numbers?
- What is the bigger number between the two numbers that have been deleted given that the difference between the two numbers is 5?
(a)
Sum of the 15 numbers
= 15 x 339
= 5085
(b)
Remaining numbers
= 15 - 2
= 13
Sum of the remaining numbers
= 318 x 13
= 4134
Sum of the two numbers
= 5085 - 4134
= 951
Smaller number = 1 u
Bigger number = 1 u + 5
Total = 1 u + 1 u + 5 = 2 u + 5
2 u + 5 = 951
2 u = 951 - 5
2 u = 946
1 u = 946 ÷ 2 = 473
Bigger number
= 1 u + 5
= 473 + 5
= 478
Answer(s): (a) 5085; (b) 478