Im not good with math sry
You gave me numbers but forgot the question. Without a question there is no answer.
Answer:
a) 5,000 b) 3,600
Step-by-step explanation:
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
You just have to multiply both by 2, and 3/4 = 6/8. 3 times 2 equals 6, and 4 times 2 equals 8. I hope I helped! :-)