Sum and product laws Quiz

1. $P(A)=0.3$, $P(B)=0.6$ and $P(A\cap B)=0.1$. Find $P(A\cup B)$.

• A. $0.8$
• B. $0.9$
• C. $0.18$
• D. $0.7$

2. $A$ and $B$ are independent with $P(A)=0.4$ and $P(B)=0.25$. Find $P(A\cap B)$.

• A. $0.65$
• B. $0.15$
• C. $0.1$
• D. $0.35$

3. Which statement must be true if $A$ and $B$ are mutually exclusive?

• A. $P(A\cap B)=P(A)P(B)$
• B. $P(A\cup B)=1$
• C. $P(A\cap B)=0$
• D. $P(A)=P(B)$

4. A bag has 4 red and 6 blue counters. Two are taken without replacement. Find the probability both are red.

• A. $\frac{4}{25}$
• B. $\frac{2}{15}$
• C. $\frac{4}{15}$
• D. $\frac{1}{5}$

5. A coin is biased with $P(\text{head})=0.6$. It is tossed three times. Find the probability of at least one head.

• A. $0.216$
• B. $0.936$
• C. $0.784$
• D. $0.4$