## You did it!

\(P(A) = \frac{n(A)}{n(U)}\)

\(P(A)+P(A')=1\)

\(P(A \cup B)=P(A) + P(B) - P(A \cap B)\)

\(P(A \cup B)=P(A) + P(B)\)

\(P(A|B) = \frac{P(A\cap B}{P(B)}\)

\(P(A \cap B) = P(A)P(B)\)

Drag each formula above onto the problem they can help solve.

There are 25 students in the class.

Five of these students are in a band.

If a student is picked at random from the class, what is the probability that they are in the band?

The probability that the train will be on time is 0.7

What is the probability the train will not be on time?

What is the probability of getting a head or a six when rolling a fair dice and tossing a normal, unbiased coin.

The probability that a student at a school is under 13 is 0.3

The probability that a student at the same school is over 16 is 0.2

If a student is picked at random from the school, what is the probability that they are either under 13 or over 16?

There are 10 red and 5 blue watches in a bag.

5 of the red watches are faulty.

3 of the blue watches are faulty.

A watch is picked out of the bag and is seen to be faulty. What is the probability that it is red given that it is faulty?

The probability that it will rain tomorrow is 0.7

The probability that a student in this class will have their birthday tomorrow is 0.45

What is the probability that both of these events will happen?