FUNDAMENTALS OF BUSINESS MATHEMATICS AND STATISTICS I 9.7Therefore, the probability (one red and one white) =^2455Example 7 :
Tickets are numbered from 1 to 100. They are well shuffled and a ticket is drawn at random. What is the
probability that the drawn ticket has :
(a) an even number,
(b) a number 5 or a multiple of 5,
(c) a number which is greater than 75,
(d) a number which is a square?
Solution:
(a) The total number of exhaustive, mutually exclusive and equal cases is 100. There are 50 even numbered
tickets.
Therefore, favourable cases to the event is 50.
Therefore, the probability =100 250 1=
(b) Suppose A denotes the number of happenings that the drawn ticket has a number 5 or a multiple of
- These are 20 cases i. e., 5, 10, 15, 20,...100.
Therefore, P(A)=100 520 1=
(c) There are 25 cases, which have a number greater than 75. Say A will denote it.
Therefore, P(A)=100 425 1=(d) There are 10 favourable cases which give squares between 1 and 100 i.e., 1, 4, 9, 16, 25, 36, 49, 64, 81,
100.
Therefore, P(A)=100 1010 1=
Example 8 :
Four cards are drawn from a pack of 52 cards without replacement. What is the probability that they are all
of different suits?
Solution :
The required probability would be :
1 39 26 13 2,197
×51 50 49 20,825× × =