Question

Each month Liz pays $35 to her phone company just to use the phone. Each text she sends costs her an additional $0.05. In March her phone bill was $72.60. In April her phone bill was $65.85. How many texts did she send each
month?

Answer 1

First let's set up an equation: 35+0.05t. 
35 is the phone rate per month plus the number of texts (t) times 0.05 (cost of 1 text)

Now we can find the amount of texts she sent each month.

March
 35+0.05t=72.60
-35               -35
0.05t=37.60
------   -------
0.05    0.05
t=752

April
 35+0.05t=65.85
-35            -35
0.05t=30.85
------   -------
0.05    0.05
t=617

She sent 752 texts in March and 617 texts in April.