JAMB - Mathematics (2021 - No. 23)
The mean of ten positive numbers is 16. When another number is added, the mean becomes 18. Find the eleventh number
3
16
38
30
解释
Mean of 10 numbers = 16
The total sum of numbers = 16 x 10 = 160
Mean of 11 numbers = 18
Total sum of numbers = 11 x 18
= 198
The 11th no. = 198 - 160
= 38
The total sum of numbers = 16 x 10 = 160
Mean of 11 numbers = 18
Total sum of numbers = 11 x 18
= 198
The 11th no. = 198 - 160
= 38