In a certain community, 30% of the families own a dog, and 20% of the families that own a dog also own a cat. it is also known that 27% of all the families own a cat.
what is the probability that a randomly selected family owns both a dog and a cat?
what is the conditional probability that a randomly selected family doesn't own a dog given that it owns a cat?

a) 0.06

b) 0.778

Step-by-step explanation:

Let's suppose a community of 100 families just to facilitate the calculation.

30% of the families own a dog

Dog = 30% of 100 = 30

20% of the families that own a dog also own a cat = 20% of 30 = 6

27% of all the families own a cat = 27% of 100 = 27

So, 6 families own a dog and a cat.

As 30 families own a dog, [30 - 6 =] 24 families own only dogs

As 27 families own a cat, [27 - 6 = ] 21 families own only cats

See picture attached.

a) What is the probability that a randomly selected family owns both a dog and a cat?

P(dog and cat) = dog ∩ cat/total = 6/100 = 0.06

b) What is the conditional probability that a randomly selected family doesn't own a dog given that it owns a cat?

So, only cat/total cat

P (not dog|cat) = 21/27 = 0.778

54 km / hours

step-by-step explanation:

we need to convert seconds to hours

60 seconds = 1 minutes

60 minutes = 1hour

15 m         60 second   60 minutes

  * *         = 54000 meters/ hour

second     1 minute             1 hour

now we need to convert meters to km

1000 m = 1 km

54000 m       1 km

*   = 54 km / hours

hour               1000m

step-by-step explanation:

step 1: solve one of the equations for one of the variables. let's solve the first equation for y:

step 2: substitute that equation into the other equation, and solve for x.

step 3: substitute x = 4 x = 4 x=4 into one of the original equations, and solve for y.