In addition to being grouped into four types, human blood is grouped by its Rhesus (Rh) factor. The distribution of these groups for Americans is given below.

Question

In addition to being grouped into four types, human blood is grouped by its Rhesus (Rh) factor. The distribution of these groups for Americans is given below. 

           O            A               B              AB

RH +      37 %          34 %            10 %           4 %

RH -       6 %           6 %              2 %           1 %

Choose one American at random. Find the probability that the person

-       A.       B.       C.       D.	Has O - negative blood
-       A.       B.       C.       D.	Has type O blood given that the person is Rh+
-       A.       B.       C.       D.	Has A + or AB - blood
-       A.       B.       C.       D.	Has Rh- given that the person has type B blood
A.	0.35
B.	0.06
C.	0.453
D.	0.167

Answer 1

Complete the table by filling in the totals like this (but drop the percentage so it's easier to comprehend):

Then you can see that the probability a person has O negative blood is 6/100.

Given a person is Rh +, you can see that type O blood he Rh + is 37 people out of 85 people (look only in the Rh+ row) or (37/85)

The total that have A+ is 34 and the total that is AB- is 1, adding those gives you 35 out of the total of 100 (35/100)

Given that a person has Type B blood (only look at the Type B column) means there are 12 in that population, The number that is Rh- is 2 so the probability is (2/12)