Question

Sandi's meal cost $18.86, including a 15% tip. What was the total cost of the meal before the tip was added? Set up your equation as you did for $64.2.

Answer 1

$16.4 is the equation x(1+0.15=18.86)

Answer 2

`\$16.4`

1) Given that the meal cost $18.86 and there was an inclusion of 15% of this as a tip we can find the original cost, using an equation:

`\begin{gathered} x(1+0.15)=18.86 \\ 1.15x=18.86 \\ (1.15x)/(1.15)=(18.86)/(1.15) \\ x=16.4 \end{gathered}`

Note that the factor (1 +0.15) refers to the 15% added to the original cost. Dividing both sides, we get the original cost.

2) Thus, the original cost was $16.4