Question

It costs $0.05 to send a text message and $0.10 to send a picture on your cell phone. You spend $4 and send five more text messages than pictures. How many text messages, x, and pictures, y, did you send?

Answer 1

The first thing we must do for this case is to define variables:
 x: text messages
 Y: pictures
 We write the system of equations:
 0.05x + 0.10y = 4
 x = y + 5
 Solving the system we have:
 x = 30
 y = 25
 Answer:
 you send:
 30 text messages
 25 pictures