Question

How many different 5 digits numbers can be made from the first 7 whole numbers, using each digit only once?

Answer 1

Answer:

2160

Step-by-step explanation:

Please find the attached images.

Answer 2

Answer:

we make 2520 five digit numbers from the first 7 whole number.

Step-by-step explanation:

Suppose, there are 5 places in which you will fill a number to make a 5 digit number.

So for the first place you have all the 7 numbers available with you,

but for the second place you can use only remaining 6 numbers ,

since you want to use each digit only once.

Similarly for the third place, you have 5 numbers left and so on.

Therefore total number of 5 digits number that can be formed from first 7 whole numbers, using only each digit only once will be

7×6×5×4×3 = 2520

this is a question of Permutations.

we can solve this question by a formula as well

npr= n! /(n-1)

where n is total numbers

P is permutation

r is how many digit numbers we have toget.