Answer:
See explanation
Step-by-step explanation:
Let
x = number of messages Salma sent
x + 9 = number of messages Brian sent
2(x + 9) = number of messages Chang sent
Total messages sent = 55
x + (x + 9) + 2(x + 9) = 55
x + x + 9 + 2x + 18 = 55
4x + 27 = 55
4x = 55 - 27
4x = 28
x = 28/4
x = 7
Number of messages Salma sent = x = 7 messages
Number of messages Brian sent = x + 9
= 7 + 9
= 16 messages
Number of messages Chang sent = 2(x + 9)
= 2(7 + 9)
= 2(16)
= 32 messages
