Martina, Hong, and Felipe sent a total of 91 text messages over their cell phones during the weekend. Hong sent 9 more messages than Martina. Felipe sent 2 times as many messages as Hong. How many messages did they each send?

M = 16

H = 25

F = 50

Step-by-step explanation:

Let's use for abbreviation M for Martina's messages, H for Hong's messages and F for Felipe's messages.

Now we need to write the given information as equations.

Martina, Hong, and Felipe sent a total of 91 text messages

(1) M + H + F = 91

Hong sent 9 more messages than Martina.

(2) H = M + 9

Felipe sent 2 times as many messages as Hong

(3) F = 2 * H

Now with this system, we need to replace the letters to leave only M in the first equation.

(4) M + (M + 9) + (2 * (M + 9) = 91

(5) 4*M + 27 = 91

(6) M = (91-27) / 4

Then we find the answer:

M = 16

H = 25

F = 50