Question

Lashonda purchased a prepaid phone card for $20. Long distance calls cost 8 cents a minute using this card. Lashonda used her card onlyonce to make a long distance call. If the remaining credit on her card is $17.12, how many minutes did her call last?

Answer 1

We know that

• Lashonda purchased a prepaid phone card for $20.

,

• Long-distance calls cost 8 cents a minute.

,

• The remaining credit on her card is $17.12.

This problem can be expressed as

`20-0.08x=17.12`

Where x is the number of minutes.

We solve the equation for x

`\begin{gathered} -0.08x=17.12-20 \\ -0.08x=-2.88 \end{gathered}`

Then, we divide by -0.08 the equation

`\begin{gathered} (-0.08x)/(-0.08)=(-2.88)/(-0.08) \\ x=36 \end{gathered}`

Therefore, Lashonda's call last 36 minutes.