Question

Maria has two fair coins. She flips them in the air. She believes it is equally likely they land 2 heads, 2 tails, or 1 head and 1 tail. Which of the following statements is NOT true?
Answers:
A. The probability of 2 heads is 25 %.
B. The probability of 1 head and 1 tail is 33 %.
C. The probability of 2 heads is less than the probability of 1 head and 1 tail.
D. The probability of either 2 heads or 2 tails is the same as the probability of 1 head and 1 tail.

Answer 1

Maria has it wrong.
Can you come up with all the possible outcomes of this coin toss?

Answer 2

... umm ok?

Answer 3

Fill in this table:

Remember, each coin can only have an outcome of heads or tails.

Answer 4

Tail Tail
Head Head
Head Tail
Tail Head

Answer 5

Right. How many possible different outcomes are there?

Answer 6

Four

Answer 7

It is either B or C I cannot decide

Answer 8

Good. There are 4 possible outcomes.
1 outcome out of 4 is 2 heads (25% probability)
1 outcome out of 4 is 2 tails (25% probabilty)
2 outcomes out of 4 are 1 heads and 1 tails (50% probability)

Answer 9

So it is B?

Answer 10

Correct. The probabillity of 1 heads and 1 tails is 50%, not 33%.
That's why I wrote above Maria is wrong. She thought that all three outcomes have the same probabiltity.

Answer 11

Thank you! My teacher puts topics on our semester projects that she hasn't covered yet :P

Answer 12

I guess she's challenging her students. Part of your challenge is to come to OS and ask to try to figure it out. You're welcome.