Answer:
240 minute or 4 hours
Step-by-step explanation:
We can use a ratio to solve
1/3 wall 4 walls
------------- = ----------------
20 minutes x minutes
Using cross products
1/3 x = 20 *4
1/3 x = 80
Multiple each side by 3
1/3 x* 3 = 80*3
x = 240 minutes
Divide each side by 60 to change to hours
x = 240/60
x = 4 hours
