# On the situation where taking the numbers 123456 how many numbers can u form using 3 digits with no numbers repeated is that a permutation or combination?

Jul 12, 2016

Combination followed by permutation: $6 {C}_{3} X 3 {P}_{3} = 120$

#### Explanation:

Selection of 3 from 6 can be done in $6 {C}_{3} = \frac{6 X 5 X 4}{1 X 2 X 3} = 20$ ways.

From each selection of 3 distinct digits, the digits can be

arranged, differently, in $3 {P}_{3} = 3 X 2 X 1 = 6$ ways.

So, the number of 3-git numbers formed = the product

20X6=120.