Final answer:
Huck can paint the fence by himself in 1 hour and 15 minutes, as determined by subtracting Tommy's work rate from their combined work rate and then finding the reciprocal of Huck's rate.
Step-by-step explanation:
To find out how fast Huck can paint the fence by himself, we need to understand the concept of work rates. Tommy's rate of painting the fence is one fence in 5 hours, so his rate is 1/5 of a fence per hour. When Huck helps Tommy, together they can paint the fence in 1 hour, so their combined rate is 1 fence per hour. To find Huck's rate, we want to subtract Tommy's rate from their combined rate.
The combined rate is 1 fence per hour, and Tommy's rate is 1/5 of a fence per hour, so Huck's rate would be:
1 fence/hour - 1/5 fence/hour = 4/5 fence/hour.
Therefore, Huck could paint the fence by himself in 5/4 hours, or 1 hour and 15 minutes, because 1 divided by 4/5 is equal to 5/4.