Question

How many two digit positive integers can be formed from the digits 1, 3, 5, and 9, if no digit is repeated?

Answer 1

The answer is 12

All possible units are 13, 15, 19, 31, 35, 39, 51, 53, 59, 91, 93, 95

Answer 2

12 two digit positive integers can be formed

Explanation:

Find the number of two digit positive integers can be fromed from the digits 1, 3, 5, and 9, if no digit is repeated

we are given with 1,3,5 and 9 that is 4 numbers

we need to frame a two digit positive integer

First digit uses all the 4 numbers

second digit use the remaining 3 numbers

So 4* 3= 12 two digit positive integers can be formed