Q: The ratio of the number of canoes for rent to the number of kayaks for rent is 8 to 5. There are 20 kayaks for rent. Write and solve a proportion to find the number of canoes for rent.
A: The information from the problem tells me:
8 canoes for every 5 kayaks. I can write this like a fraction:
8 canoes / 5 kayaks
Now, I know there are 20 kayaks and want to to find the canoes… So,
8 canoes / 5 kayaks = ? canoes / 20 kayaks
Putting this more mathematically (taking out the words):
8/5 = x/20
So, now we must solve for x (get x by itself)…. Currently, x is being divided by 20. To “get rid of” the division, I will just multiply both sides by 20 to cancel it out like so:
(8/5)*20 = (x/20)*20
(Notice, this is the same as multiplying by 20/1 like so):
(8/5)*(20/1) = (x/20)*(20/1)
Multiply fractions across the top and across the bottom:
160/5 = 20x/20
32 = x.
The number of canoes is 32.