(1) Information in the figure: Type O blood accounts for 40% of the class, and Type B blood accounts for 24% of the class.

8÷(40%-24%)

=8÷ 16%

=50 (person)

There are 50 people in this class.

(3) Question: How many people have type A blood than type B blood?

50×(28%-24%)

=50×4%

=2 (person)

There are two more people with type A blood than those with type B blood.