Question

2 In a medical study, patients are classified in 8

ways according to whether they have blood type AB+,

AB−, A+, A−, B+, B−, O+, or O−, and also accord￾ing to whether their blood pressure is low, normal, or

high. Find the number of ways in which a patient can

be classified.

Answer 1

The number of blood types $n_1=8,$ the number of blood pressure types $n_2=3,$

the total number of ways in which a patient can be classified

$N=n_1\cdot n_2=8\cdot3=24.$