Answer:
11 months
Step-by-step explanation:
the math that i did was i kept adding 400 to 2500 and counted every four hundred that i added witch was 11 until i got to 7000 so the answer is 11 months. You will have some left over which you will have 300 left over.
Here's link to the answer:
cutt.us/tWGpn
21 should be the right answer
