Question

Suppose an ATM PIN must consist of 6 numbers from the digits 0, 1, 2, 3, 4, 5, 6, 7, 8, and 9, with repeats allowed. For example, an acceptable PIN could be 955123.

1. How many possible ATM PINs are possible?
2. If someone had one attempt to guess an ATM PIN, what is the probability they would guess correctly with one attempt?

Answer 1

1) the no. of possible pins are 6×5×4×3×2×1

=720

2) the probability is 1/720