Find the number of positive three-digit integers whose digits are among 9, 8, 7, 5, 3, 1 in which none of the digits are the same.
15
120
216

120

Step-by-step explanation:

The given digits : 9, 8, 7, 5, 3, 1

Number of digits : 6

If repetition of digit is not allowed then we use permutations.

We know that the number of permutations of n things taking r at a time is given by :-

Now, the number of permutations of 6 digits taking 3 at a time is given by :-

answear:

a

step-by-step explanation: a

step-by-step explanation:

you divide the denominator by the numerator on both sides and if the quotients are equal then the fractions are equivalent