Question

Cell phone company A charges $20 per month plus $0.05 per text message. Cell phone company B charges $10 per month pus $0.07 per text message. Is there any number of text messages that will result in the exact same charge from both companies?

Answer 1

Yes. 500

Explanation:

If x is the number of text messages per month, company A charges `20 +0.05*x` and company B charges `10 + 0.07*x`
If the charge is the same then
`20 + 0.05*x = 10 + 0.07 *x`
`20 - 10 = 0.07 *x - 0.05*x`
`10 = 0.02 *x`
`x = 10/0.02 = 10 / (2/100) = 10*100/2 = 500`