Question

it costs $0.07 to send a text message and $0.12 to send a picture on your cell phone. You spend $3.38 and send twice as many text messages as pictures. How many text messages did you send?

Answer 1

Let text message is m
it costs $0.07 to send a text message
so total cost of sending txt msg = 0.07m

Let picture is p
it costs $0.12 to send a picture
total cost of sending pics = 0.12p


You spend $3.38:
means: 0.07m + 0.12p = 3.38

AND

You send twice as many text messages as pictures:
means: m = 2p


solving these two equations together:

0.07m + 0.12p = 3.38
m = 2p
-----------------------------
yields:

m = 26
p = 13


You sent 26 text messages and 13 pictures on your cell phone

Answer 2

26 text messages.

Explanation:

Let T the amount of text messages and P the amount of pictures. Now,

T = 2P. Then,

3.38 = 0.07(2P) + 0.12(P)

3.38 = 0.14P + 0.12 P

3.38 = 0.26P

P = 3.38/(0.26)

P = 13. Then, you sent 13 pictures and T = 13*2 = 26 text messages.