Question

) How many four-digit numbers csan be formed from the digits 1,3,5,7,8, and 9 if each digit can be used at most once in each number?

Answer 1

the number of combinations of 4 from 6 =6!/4 !* 2! = 15
each of these 4 digit numbers can be arranged in 4! ways - 24 wYS

SO TOTal no. of ways = 15*24 = 360