Question

The digits 1, 2, 3, 4 and 5 are randomly arranged to form a three digit number. The digits are not repeated. What is the proabability the number is even and greater than 500?

Answer 1

1/10

Explanation:

There are 5·4·3 = 60 ways to choose a 3-digit number from 5 digits (no repeats).

There re 1·2·3 = 6 ways to choose a number 5x2 or 5x4 from those digits.

The probability of randomly choosing one of 60 that is one of the 6 is ...

... 6/60 = 1/10