A camp cook estimates that 9 boxes of macaroni and cheese will feed 75 campers. At this rate, how many boxes should be purchased to feed 130 campers?

Well first lets find out how many campers one box will feed

we can find this by doing 75/9

75/9 is 8.3333 (.3333 keeps repeating)

Now that we know that and we know we need to feed 130 campers

we can do 8.3333 /130

This is 15.6

15.6 boxs, you cant buy 0.6 of a box so lets just round up to 16

we can check this math by doing

15.6 * 8.33333333 which we can see equals 130

since we rounded up lets do 16 * 8.33333333

This is 133.3333333 so a little more but again we had no choice since we cant buy 0.6 of a box

the answer is 16