Question

The blood groups of 200 people are distributed as follows: 50 have type A blood, 65 have B blood type, 70 have O blood type and 15 have type AB blood. If a person from this group is selected at random, what is the probability that this person has O blood type? 

Construct a table of frequencies for the blood groups

Answer 1

the probability that this person has O blood type:

$70/200=7/20$

table of frequencies:

blood type frequency

A 50

B 65

O 70

AB 15