jmc

Question

Lark has forgotten her locker combination. It is a sequence of three numbers, each in the range from 1 to 30, inclusive. She knows that the first number is odd, the second number is even, and the third number is a multiple of 3. How many combinations could possibly be Lark's?

Accepted Answer

There are 15 odd numbers, 15 even numbers, and 10 multiples of 3, making for 15^2 10 = 225 10 = 2250 combinations total.