Question

The mean of 5, 15, 8, z, 12 is 10. What is the value of z?​

Answer 1

Answer:

To get the arithmetic mean of a set of numbers, we add them all up, and then divide by how many numbers there are in the set.

Here, we add up 2 + 3 + 5 + 8 + Z + 10 + 12, which gives us Z + 40.

There are 7 numbers, so we divide by 7 to get (Z + 40) / 7 for the arithmetic mean.

We are told the arithmetic mean is 7, so (Z + 40) / 7 = 7.

Z + 40 = 49

Z = 9

(You can now go back and check that Z = 9 works).