Probability
5 Questions Your Maths Teacher Can Ask To Confuse You
Q1: A fair coin is tossed twice, find the probability of getting different outcomes of this experiment. What will be the sum of all these probabilities?
Answer: A coin is tossed twice, the sample space (possible outcomes) will be:
S = {HH, HT, TH, TT}
Let A be the event getting two heads then
| Number of Favourable Outcomes for event A | 1 | ||
| P(A) = |  |
= | |
| Total Number of Outcomes | 4 |
Let B be the event getting first head and then tail (HT) then
| Number of Favourable Outcomes for event B | 1 | ||
| P(B) = | |
= | |
| Total Number of Outcomes | 4 |
Let C be the event getting first tail then head (TH) then
| Number of Favourable Outcomes for event C | 1 | ||
| P(C) = | |
= | |
| Total Number of Outcomes | 4 |
Let D be the event getting two tails (TT) then
| Number of Favourable Outcomes for event D | 1 | ||
| P(D) = | |
= | |
| Total Number of Outcomes | 4 |
Sum of all probabilities P(A) + P(B) + P(C) + P(D) = 4/4 = 1
Q2: Find the probability that a leap year selected randomly will have 53 Sundays?
(Note: If first two days lands on a Sunday in a leap year it would have 53 Sundays. How to prove?).
