Question

10.) 0.4(n + 20) = 12.4

Explanation:

Step1: Divide both sides by 0.4

$\frac{0.4(n + 20)}{0.4} = \frac{12.4}{0.4}$
$n + 20 = 31$

Step2: Subtract 20 from both sides

$n + 20 - 20 = 31 - 20$

Answer:

$n = 11$