A bank PIN is a string of four digits, each digit 0-9. (a) How many choices are there for a PIN if the last digit must be odd? M
ake sure to explain your answer. (b) How many choices are there for a PIN if the last digit must be odd and all the digits must be different from each other? Make sure to explain your answer.
a) there are four different slots, and for the first three slots there are a possibility for 10 different numbers and in the last slot there can only be 5 different numbers. So you get 10 x 10 x 10 x 5 which leaves you with 5,000 possibilities
b) the same thing as above but know you have fewer numbers 10 x 9 x 8 x5 which gives you 3,600 possibilities
