Question

Ricky took the SAT math test four times the first three scores total 1900 after the 4th time is average score with 650 what score did he get the 4th time

Answer 1

(1900 + x) / 4 = 650 therefore x = 700. The 4th score was 700.

Answer 2

Ricky scored 700 points the 4th time.

Explanation:

By definition the average formula is:

`average = (x_1 + x_2 + x_3 + ... + x_n)/(n)`

where x are the samples of the data set and n the numbers of elements in the set.

In this case:

• n = 4

• average = 650
• x₁ + x₂ + x₃ = 1900

Replacing the data on the general formula:

`average = (x_1 + x_2 + x_3 + x_4)/(n)`

`650 = (1900 + x_4)/(4)` //multiply both sides of the equation by 4.

`4 * 650 = (1900 + x_4)/(4) * 4`

`2600 = 1900 + x_4` //substract 1900 in both sides of the equation.

`2600 - 1900 = 1900 - 1900 + x_4`

`700 = x_4`