Answer:
Make an equation in the form of y=mx+b
b is the number of cards that she started with, because if x=0, the number of hours is zero, then she would have the number of cards she has now.
y=mx+3
M is the rate of change, how many cards she makes in one hour, which is 5.
y=5x+3
Now, find the number of cards after 6 hours
y=5(6)+3
y=30+3
33 cards
