The Blood group table of 30 students of class IX is recorded as follows:
A, B, O, O, AB, O, A, O, B, A, O, B, A, O, O
A, AB, O, A, A, O, O, AB, B, A, O, B, A, B, O
A student is selected at random from the class from blood donation. Find the probability that the blood group of the student chosen is:
1: A
2: B
3: AB
4: O
1. Probability of a student having blood group A
$=\frac{\text { Favorable out come }}{\text { Total out come }}$
= 9/30
= 0.3
2. Probability of a student having blood group B
$=\frac{\text { Favorable out come }}{\text { Total out come }}$
= 6/30
= 0.2
3. Probability of a student having blood group AB
$=\frac{\text { Favorable out come }}{\text { Total out come }}$
= 3/30
= 1/10 = 0.10
4. Probability of a student having blood group O
$=\frac{\text { Favorable out come }}{\text { Total out come }}$
= 12/30 = 0.4