A list of 18 numbers has an average of 345. When two numbers are deleted from the list, the average of the remaining numbers is 318.
- What is the sum of 18 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 18 numbers
= 18 x 345
= 6210
(b)
Remaining numbers
= 18 - 2
= 16
Sum of the remaining numbers
= 318 x 16
= 5088
Sum of the two numbers
= 6210 - 5088
= 1122
Smaller number = 1 u
Bigger number = 1 u + 4
Total = 1 u + 1 u + 4 = 2 u + 4
2 u + 4 = 1122
2 u = 1122 - 4
2 u = 1118
1 u = 1118 ÷ 2 = 559
Bigger number
= 1 u + 4
= 559 + 4
= 563
Answer(s): (a) 6210; (b) 563