A list of 15 numbers has an average of 345. When two numbers are deleted from the list, the average of the remaining numbers is 325.
- 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 4?
(a)
Sum of the 15 numbers
= 15 x 345
= 5175
(b)
Remaining numbers
= 15 - 2
= 13
Sum of the remaining numbers
= 325 x 13
= 4225
Sum of the two numbers
= 5175 - 4225
= 950
Smaller number = 1 u
Bigger number = 1 u + 4
Total = 1 u + 1 u + 4 = 2 u + 4
2 u + 4 = 950
2 u = 950 - 4
2 u = 946
1 u = 946 ÷ 2 = 473
Bigger number
= 1 u + 4
= 473 + 4
= 477
Answer(s): (a) 5175; (b) 477