Question

How many numbers more than 3500can be made by using the digits 1,2,5,6,7 with no repetition?

Answer 1

number is greater than 3500 if first digit is 5,6,7
first digit can be chosen in 3 ways
second digit in 4 ways
third digit in 3 ways
fourth digit in 2 ways
and last digit in 1 ways
total numbers formed more than 3500 with no repetition are 3×4×3×2×1=72