In the previous section, you interpreted equations within a certain situation. In this section, we will find solutions to equations when given information and interpret the solutions within the context of the situation.

Linh has a cell phone plan. She has unlimited talk time but pays for each text message that she sends. Her cell phone bill, before taxes and fees, is calculated by the following equation, where b represents the amount of the bill, and m represents the number of text messages that Linh sends:

b = 75 + 0.15m

Interactive exercise. Assistance may be required. The number of messages that Linh sent for each of the last four months is shown. Click and drag each amount to match the number of messages sent for that amount.


The Baba family is taking a road trip around Texas and its surrounding states. Majida uses the equation d = 65t, where d represents the distance driven and t represents the time it takes, to estimate the time it will take to drive between two cities.

The map of Texas shows major interstate highways along with some cities inside Texas and in neighboring states.

Interactive exercise. Assistance may be required. Drag each route onto its place on the map (note that not all of the roads on the map are in red). Once you correctly drag a route to the map, the distance between the two cities shows up below the map. Use that information to calculate the amount of time it takes the Baba family to drive between the two cities.


Houston to Fort Worth

Interactive popup. Assistance may be required.

Check Your Answer

4 hoursClose Pop Up

Fort Worth to Amarillo

Interactive popup. Assistance may be required.

Check Your Answer

51 over 4 1 4 hoursClose Pop Up

Amarillo to Albuquerque

Interactive popup. Assistance may be required.

Check Your Answer

41 over 2 1 2 hoursClose Pop Up

Albuquerque to El Paso

Interactive popup. Assistance may be required.

Check Your Answer

4 hoursClose Pop Up

El Paso to San Antonio

Interactive popup. Assistance may be required.

Check Your Answer

81 over 2 1 2 hoursClose Pop Up

San Antonio to Houston

Interactive popup. Assistance may be required.

Check Your Answer

23 over 4 3 4 hoursClose Pop Up

Practice

Interactive exercise. Assistance may be required. Use the same formula to determine the total cost of a purchase of 5 shirts at $23.50 each, including a 6% sales tax. Use the grid below to record your answer. Type your answer in the boxes in front of and behind the decimal. Click inside each box to enter the numeral that belongs in the box. Click the bubble beneath the numeral to shade the bubble that matches the numeral.