Question

the mean of eight numbers is 4.5.give that the seven of the numbers are 9,2,3,4,12,13,1.find the eighth number

Answer 1

-8

Explanation:

Use the mean formula:

mean = sum of elements / number of elements

Let x represent the 8th number, and plug this and the other numbers into the formula:

(9 + 2 + 3 + 4 + 12 + 13 + 1 + x) / 8 = 4.5

Simplify and solve for x

(44 + x) / 8 = 4.5

44 + x = 36

x = -8

So, the 8th number is -8