A list of 15 numbers has an average of 346. When two numbers are deleted from the list, the average of the remaining numbers is 309.
- 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 1?
(a)
Sum of the 15 numbers
= 15 x 346
= 5190
(b)
Remaining numbers
= 15 - 2
= 13
Sum of the remaining numbers
= 309 x 13
= 4017
Sum of the two numbers
= 5190 - 4017
= 1173
Smaller number = 1 u
Bigger number = 1 u + 1
Total = 1 u + 1 u + 1 = 2 u + 1
2 u + 1 = 1173
2 u = 1173 - 1
2 u = 1172
1 u = 1172 ÷ 2 = 586
Bigger number
= 1 u + 1
= 586 + 1
= 587
Answer(s): (a) 5190; (b) 587