Question

From the number 0,1,2,3,4,5

a. how many 2-digit number can be made if repetition is not allowed
b. how many 4-digit number less than three thousand can be made if repetition is allowed
c. how many 4 digits numbers greater than 4000 can be made if repetition is not allowed

Answer 1

25, 432, 120

Explanation:

a. 5 × 5 = 25 ways

b. 2 × 6 × 6 × 6 = 432 ways

c. 2 × 5 × 4 × 3 = 120 ways