How many 3-digit numbers can be formed the digits 2, 3, 4, 5, 6,7 and 9, which are divisible by 5 and none of the digits is repeated?
সমাধান
সঠিক উত্তর: Option D
As the 3 digit number must be a multiple of 5, it must have 5 in its units place
Ex: xy5. X and Y can be any of the remaining 5 digits(2,3,6,7,9).
These remaining 5 digits can have 5p2 permutations ( P- because the arrangement is important). 5p2 =20.
That gives 20 possible arrangements of the 5 digits.
