Question

An amusement park has 20 rides. Ethan has enough time to ride 3 rides before the park closes. How many different ways could Ethan pick to ride the 3 rides?

Answer 1

20*19*18 = 6840

UNLESS...............

he is allowed to ride the same ride again , over and over....

then it is 20 x 20 x 20 = 8000