Question

a jar contains white, red and blue marbles. the probability of pulling a red marble is 0.3 and a blue marble 0.45. what is the probability of pulling a white marble?

Explanation:

Step1: Recall probability sum formula

The sum of probabilities of all possible outcomes is \(1\). Let \(P(\text{white})\), \(P(\text{red})\), \(P(\text{blue})\) be the probabilities of pulling white, red, and blue marbles respectively. So \(P(\text{white})+P(\text{red})+P(\text{blue}) = 1\).

Step2: Substitute known values

Given \(P(\text{red})=0.3\) and \(P(\text{blue}) = 0.45\). Then \(P(\text{white})=1-(P(\text{red}) + P(\text{blue}))\).

Step3: Calculate

\(P(\text{white})=1-(0.3 + 0.45)=1 - 0.75=0.25\)

Answer:

\(0.25\)