Question

A cell phone plan charges $15 a month plus $0.10 per minute for phonecalls. Gertrude paid $32.50 last month forminutes of phonecalls

Answer 1

This celphone plan has a fixed cost of $15, this means that regarding if you use it or not, you'll pay at least $15.

Also, added to those fixed costs, you pay $0.10 per minute for phone calls.

Acording to the text, the bill for last month was $32.50, first step is to remove the fixed charges to know how much was spent on phone calls:

$32.50-$15= $17.5

Now using cross multiplication you can calculate how many minutes she talked to spend $17.5:

$0.10____1min

$17.50___xmin

$x=\frac{17.50\cdot1\min }{0.10}=175\min$

She talked 175 minutes over the phone