P(only A) and P(only B)

Q. If A and B are two events associated with a random experiment for which $P\left(A\right)=0.35,P\text{(A or B)}=0.85,\text{and P(A and B)}=\mathrm{0.15.}$Find P(only B).

1. 0.85
2. 0.5
3. 0.36
4. 0.75

Q. If A and B are mutually exclusive events $P\left(A\right)=\frac{3}{8}\text{and}P\left(B\right)=\frac{1}{8},\text{then find}P(A^{\prime }\cup B^{\prime }).$

1. 1
2. 0
3. 0.8
4. 0.5

Q. $A$ & $B$ are two independent events such that $P\left(\overline{A}\right)=0.7,P\left(\overline{B}\right)=a$ & $P(A\cup B)=0.8$, then $a=$

1. $5/7$
2. $1$
3. $2/7$
4. None

Q.

Represent 0.45 as a rational number.

1. $\frac{4}{5}$

2. $\frac{9}{2}$

3. $\frac{5}{4}$

4. $\frac{9}{20}$