Answer:
Five bags of dog food costs $21.25.
Step-by-step explanation:
We can solve using proportions.

z is directly proportional to x: z = kx.
If z is directly proportional to x and inversely proportional to y, then z = Kx/y.
When x= 6 and y = 6, z is 12. Find the constant of proportionality, K:
12 = K(6/6), or K = 12
Then, in general, z = 12x/y.
What is z when x=13 and y=10? z = 12(13)/(10) = 15.6 (answer)
Answer:
Sixth day
Step-by-step explanation:
Keep adding 2 until you get to 13