Question

Given the digits 2,5,7,9, 4, and 1, how many 4-digit codes can be made if 4 points

the first digit must be even and the last digit must be greater than 6?
80
120
48
144

Answer 1

144

Explanation:

first digit of the code: only 2 and 4 are the only even numbers availible, so only 2 possibilities for the first digit.

2nd digit of code: 2,5,7,9,1 so 6 possibilities for the 2nd digit.

3rd digit of code: 2,5,7,9,1 so 6 possibilities for the 3rd digit.

4th digit of code: only 7 and 9 are greater tyhan 6 so only 2 possibilities for the 4th digit.

SO...

2 x 6 x 6 x 2 = 144