A class has 30 students. In how many ways can three prizes be awarded so that:
(a) no students get more than one prize?
(b) a student may get any number of prizes?
(a) Number of ways in which the first prize can be awarded = 30
m = 30
Number of eligible students for the second prize = 29
∴ Number of ways in which second prize can be awarded = 29
n = 29
Number of ways in which the third prize can be awarded = 28
P = 28
∴ By fundamental principle of counting, the total number of ways of awarding the three prizes.
=
(b) Number of students = 30
Number of ways in which the first prize may be awarded = 30
m = 30
Number of students eligible for the second prize = 30 (∵ A student may get any number of prizes)
Number of ways in which the second prize can be awarded = 30
n = 30
Similarly, number of ways in which the third prize can be awarded = 30
p = 30
By fundamental principle of counting, the number of ways in which the three prizes can be awarded
=
How many 3-digit numbers can be formed from the digits 1, 2, 3, 4 and 5 assuming that repetition of the digits is allowed.
How many 3-digit numbers can be formed from the digits 1, 2, 3, 4 and 5 assuming that repetition of the digits is not allowed.