Question

How many four digit numbers may be formed using the elements from the set {1, 2, 3, 4, 5, 6, 7} if no elements can be repeated in the number?

Answer 1

32 elements are formed

Answer 2

1st digit and 2nd digit and 3rd digit and 4th digit (with no repeats)

7 x 6 x 5 x 4

7 x 6 x 5 x 4 = 840

Answer: 840 four-digit numbers