Answer:
1
Step-by-step explanation:
The difference of 12 and 9 is 12 - 9 = 3
Then 3 ÷ 3 = 1
The 4th number is 10, since you need to add 10 to get 32 so that when you divide by 4 you get 8
Part a: the first cereal is y=7x and the second one is y=10x so they are $3 apart.
part b: y=7*4 (28) and y=10*4 (40) is $12 apart so she will save $12 each month.