You receive 9 text messages in 12 minutes. what is the rate of text messages per hour?

Remember 60 mins per hour
9 per 12
use ratio and proportion
9:12=x:60
9/12=x/60
multiply both sides by 60
540/12=x
45=x
the answer is 45

a shortcut is yo know that 12 times 5=60 so
9 times 5=answer since 12 times 5=60

answer isi 45