A list of 18 numbers has an average of 331. When two numbers are deleted from the list, the average of the remaining numbers is 312.
- 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 331
= 5958
(b)
Remaining numbers
= 18 - 2
= 16
Sum of the remaining numbers
= 312 x 16
= 4992
Sum of the two numbers
= 5958 - 4992
= 966
Smaller number = 1 u
Bigger number = 1 u + 4
Total = 1 u + 1 u + 4 = 2 u + 4
2 u + 4 = 966
2 u = 966 - 4
2 u = 962
1 u = 962 ÷ 2 = 481
Bigger number
= 1 u + 4
= 481 + 4
= 485
Answer(s): (a) 5958; (b) 485