Answer:
0.667
Step-by-step explanation:
Data provided:
x 0 1 2 3 4 5 6
P(X = x) 0.10 0.20 0.40 0.15 0.05 0.05 0.05
Now,
The probability that less than 5 items will be sold in a week given that 3 items have already been sold can be calculated as;
P ( less than 5 items sold | 3 or more items sold )
= [tex]\frac{\textup{ 3 or more and less than 5 items sold}}{\textup{3 or more items sold}}[/tex]
= [tex]\frac{\textup{3 or 4 items sold}}{\textup{3 or more items sold}}[/tex]
or
P ( less than 5 items sold | 3 or more items sold ) = [tex]\frac{\textup{0.15 + 0.05}}{\textup{0.15 + 0.05 + 0.05 + 0.05}}[/tex]
or
P ( less than 5 items sold | 3 or more items sold ) = [tex]\frac{\textup{0.2}}{\textup{0.3}}[/tex]
or
P ( less than 5 items sold | 3 or more items sold ) = 0.667
