Question

a group of three numbers has an average of 70 in the first two are 12 and 19 what is the third number ​

Answer 1

The third number is 179 .

Explanation:

Given as :

The average of group of three numbers = n = 70

The first number = x = 12

The second number = y = 19

Let The third number = z

Now, According to question

∵ The average of group of three numbers = n

I.e n =
`(x + y + z)/(3)`

or.
`(x + y + z)/(3)` = 70

Or, x + y + z =70 × 3

Or, x + y + z = 210

Or, 12 + 19 + z = 210

Or, 31 + z = 210

or, z = 210 - 31

∴ z = 179

So, The third number = z = 179

Hence , The third number is 179 . Answer