Needs to show calculations! Thanks.

Crazy Joe operates a canoe rental service on the Guadalupe River. He currently leases 15 canoes from a dealer in a nearby city at a cost of $10 per day. On weekends, when the water is high, he picks up the canoes and drives to a launching point on the river, where he rents canoes to white-water enthusiasts for S30 per day. Lately, canoeists have complained about the unavailability of canoes, so Crazy Joe has recorded the demand for canoes and found the experience below for the past 20 days: Recommend an appropriate number of canoes to lease