Answer:
The expression for rate per hour is
.
Explanation:
Given:
A machine paints 340 toy boats in 45 minutes.
To Find:
Expression equals the rate per hour?
Solution:
Finding the expression for rate per minute:

So, rate per minute expression is
= 
Then, rate per hour expression 
So, rate per hour expression is
= 453.334 toys per hour.
Hence, the expression for rate per hour is 