Question

The average of two numbers is 20 and their SD is 5. Find the two numbers (a) 15,25 (b) 30.40 (c) 10,15 (d) None

Answer 1

a) 15, 25

Explanation:

Finding the average is to find the sum and divide it by the quantity of the numbers.

(15 + 25) / 2 = 40 / 2 = 20, 20 is the average of two numbers.

However standard deviation includes at least one degree of 2.

x1 + x2 = 40

SD = 5

=
`√([(x_1 - 20)^2 + (x_2 - 20)^2]/2 \\)= 5\\ x_1 = 15, or x_1 = 25\\x_2 = 15 or x_2 = 25`