Solving a decimal word problem using a two step linear inequality

Question

For his phone service, Hans pays a monthly fee of $19, and he pays an additional $0.06 per minute of use. The least he has been charged in a month is $90.34.What are the possible numbers of minutes he has used his phone in a month?

Use m for the number of minutes, and solve your inequality for m.

.

Answer 1

First, since the LEAST amount Hans has paid in a month is $90.34, the inequality will end with "is greater than or equal to 90.34."

Now, since m is the number of minutes, and Hans is charged $0.06 per minute, we need to have 0.06m in our inequality.

Lastly, Hans pays $19 a month, so this needs to be added to the minutes used.

The inequality will look like: 0.06m + 19 >(or equal to) 90.34

To solve:

Subtract 19 from both sides, leaving 0.06m >(or equal to) 71.34. Then, we divide both sides by 0.06 to get m by itself, which gives us m >(or equal to) 1189.

The possible number of minutes is greater than or equal to 1189.