Answer:
10 months
Step-by-step explanation:
3500 - 2000 = 1500
1500/150 = 10
Number 1 is 15 number 2 is 9x3=27 and number 3 is 15 and number 4 is 5x7=35 number number 6 is 5 number 7 is 11 and that is about all i know hope this helps
I use it as a short way to say "okay" but I don't know how others may use it.