Find the number of ways in which 6 objects out of 8 can be arranged so that two particular objects are :
(a) included (b) excluded (Hint : (a) 6P2 x 6P4 (b) 6P6)
(i) first letter is a vowel (ii) no two vowels are together
(iii) relative position of vowels and consonants remains unchanged?
(i) How many different numbers of 6-digits can be formed with the numbers 3, 5, 7, 8, 2, 6?
(ii) How many of them are divisible by 5?
(ii) no two vowels are together ?
(iii) vowels may occupy odd places ?
(i) exactly three flags can be used for a signal?
(ii) at most three flags are to be used for a signal?
(iii) at least three flags are to be used for a signal?
Total number of balls =
n = 9
Number of red balls = 4
p = 4
Number of yellow balls = 3
q = 3
Number of green balls = 2
r = 2
∴ The number of permutations of balls:
= 9 x 4 x 7 x 5 = 1260.