The arithmetic mean of 6.4 and y is 8.5. find the number y.

It is known from the condition that the arithmetic mean of 6.4 and y is 8.5. In order to find the value of y, we will compose and solve a linear equation.

Let’s first of all remember what is called the arithmetic mean of two numbers.

The arithmetic mean of numbers is equal to the sum of these numbers divided by their number. For two numbers, the arithmetic mean can be found like this:

(a + b) / 2 = m;

(6.4 + y) / 2 = 8.5;

We multiply both sides of the equation by 2 and get:

6.4 + y = 17;

y = 17 – 6.4;

y = 10.6 second number.

Answer: y = 10.6