# Your test scores are 75, 93, 90, 82 and 85. What is the lowest score you can obtain on the next test to achieve an average of at least 86?

Nov 15, 2016

I would have to score at least $91$ on the next test.

#### Explanation:

An average is calculated by adding the figures and dividing by the number of figures. Since we have $5$ given figures and $1$ awaited figure (a total of $6$) to achieve an average of 86, we can write an equation:

$\frac{75 + 93 + 90 + 82 + 85 + x}{6} = 86$

Simplify the numerator on the left.

$\frac{425 + x}{6} = 86$

Multiply both sides by $6$.

$425 + x = 86 \times 6$

$425 + x = 516$

Subtract $425$ from both sides.

$x = 91$