the time t required to empty a pool varies inversely as the rate r of the pump. One pool takes 60 minutes to empty at the rate of 230 gallons per minute.
write an equation that represents the relationship between t and r.
find the constant of variation k.
how long will it take to empty the same pool with a pump that can empty it at the rate of 300 gallons per minute?

t=\frac{k}{r}

Use your givens to find k. Then, you can find the time when r=300.