A list of 13 numbers has an average of 350. When two numbers are deleted from the list, the average of the remaining numbers is 320.
- What is the sum of 13 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 13 numbers
= 13 x 350
= 4550
(b)
Remaining numbers
= 13 - 2
= 11
Sum of the remaining numbers
= 320 x 11
= 3520
Sum of the two numbers
= 4550 - 3520
= 1030
Smaller number = 1 u
Bigger number = 1 u + 4
Total = 1 u + 1 u + 4 = 2 u + 4
2 u + 4 = 1030
2 u = 1030 - 4
2 u = 1026
1 u = 1026 ÷ 2 = 513
Bigger number
= 1 u + 4
= 513 + 4
= 517
Answer(s): (a) 4550; (b) 517