How many 3-digit numbers can be formed with the digits 1,4,7,8 and 9 if the digits are not repeated?  Choose the correct choice from the following: A) 20 B) 40 C) 60 D) 80 E) 100
Three digit numbers will have unit's, ten's and hundred's place.   Out of 5 given digits any one can take the unit's place.   This can be done in 5 ways ------- (i)   After filling the unit's place, any of the four remaining digits can take the ten's place.   This can be done in 4 ways ------- (ii)   After filling in ten's place, hundred's place can be filled from any of the three remaining digits.   This can be done in 3 ways ------- (iii)   =&gt; By counting principle, the number of 3 digit numbers =5Ã—4Ã—3==5Ã—4Ã—3= 60   ANSWER 60
<result>C</result>
How many 3-digit numbers can be formed with the digits 1,4,7,8 and 9 if the digits are not repeated?