20 cranes and turtles in the same pool, 64 feet. How many cranes and turtles are there?

Suppose all turtles lift their feet (a little nonsense, but in the routine, there should be 20 times 2=40 feet, and when the turtles put down their feet, it will be 64 feet. The extra 24 feet are just two feet put down by the tortoise, and one tortoise puts down two feet, so 24 is divided by 2= 12 turtles, so there are 8 cranes.