Question

1) Given P(A) = 0.3 and P(B) = 0.5, do the following.

Answer 1

Answer:

1) a) 0.8

b) 0.6

2) a) 0.08

b) 0.14

Step-by-step explanation:

1) Given

$P(A) = 0.3$ and $P(B) = 0.5$

Let us learn about a formula:

$P(A\ or\ B) = P(A) +P(B) -P(A\ and\ B)\\OR\\P(A\cup B) = P(A) +P(B) -P(A\cap B)$

(a) If A and B are mutually exclusive i.e. no common thing in the two events.

In other words:

$P(A\ and\ B)$ = $P(A \cap B)$ = 0

Using above formula:

$P(A\ or\ B) = P(A) +P(B) -P(A\ and\ B)\\\Rightarrow P(A\ or\ B) = 0.3 + 0.5 -0 = \bold{0.8}$

(b)  P(A and B) = 0.2

Using above formula:

$P(A\ or\ B) = P(A) +P(B) -P(A\ and\ B)\\\Rightarrow P(A\ or\ B) = 0.3 + 0.5 -0.2 = \bold{0.6}$

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1) Given

$P(A) = 0.4$ and $P(B) = 0.2$

Let us learn about a formula:

$P(A\ and\ B) = P(B) \times P(A/B)$  for dependent events

$P(A\ and\ B) = P(A) \times P(B)$ for independent events.

(a) If A and B are independent events :

Using the above formula for independent events:

$P(A\ and\ B) = 0.4 \times 0.2 = \bold{0.08}$

(b)  $P(A / B) = 0.7$

Using above formula:

$P(A\ and\ B) = P(B) \times P(A/B) = 0.2 \times 0.7 = \bold{0.14}$