Question

P (a) =0.60, p(b) = 0.25, and p(a and b) =0.15 what is p(a or b) ?

a.) 0.40
b.) 0.85
c.) 0.70
d.) 0.75

Answer 1

Answer: Option C

`P (A\ or\ B) = 0.70`

Explanation:

If A and B are events that are not mutually exciting, then it is true that:

`P (A\ or\ B) = P (A) + P (B) - P (A\ and\ B)`

In this case we know
`P(A)`,
`P(B)` and we also know
`P (A\ and\ B)`

`P(A)=0.60`

`P(B) = 0.25`

`P(A\ and\ B)=0.15`

Therefore we have that:

`P (A\ or\ B) = 0.60 + 0.25 - 0.15`

`P (A\ or\ B) = 0.60 + 0.1`

`P (A\ or\ B) = 0.70`

Answer 2

C is the correct option

Explanation:

To find the probability of P(a or b) we will use the formula:

P(a or b)= P(a)+ P(b) - P(a-b)

Now put the given values in the formula:

P(a or b)= 0.60+0.25-0.15

P(a or b)=0.85 - 0.15

P(a or b)= 0.70

Thus the correct option is C....