Question

Use the equation P(A or B)= P(B)-P(A and B) to find the missing value below.

Answer 1

Answer:

$P(B) = \frac{7}{8}$

Step-by-step explanation:

Given

P(A or B)= P(B)-P(A and B)

P(A)=1/3

P(A and B)=1/8

P(A or B)= 3/4

Required

Find P(B)

To find P(B), all we need to do is to substitute values of P(A or B) and P(A and B) in the given equation.

This goes thus;

P(A or B) = P(B) - P(A and B) becomes

$\frac{3}{4} = P(B) - \frac{1}{8}$

Make P(B) the subject of formula

$P(B) = \frac{3}{4} + \frac{1}{8}$

Take L.C.M

$P(B) = \frac{6 + 1}{8}$

Add fractions

$P(B) = \frac{7}{8}$

From the workings above, the value of P(B) using the given equation is $\frac{7}{8}$