John can clean pools at a constant rate of
3/5
pools per hour. How many pools can John clean in 10 hours?
To find out how many pools John can clean in 10 hours, we can multiply the rate at which he cleans pools by the number of hours he works.
The rate at which John cleans pools is 3/5 pools per hour.
So in 10 hours, John can clean 3/5 * 10 = 6 pools. Answer: \boxed{6}.