Question

What is the probability that the number of “HEADs” on these four coins is equal to 3? (4 points)

Answer 1

Answer:

a. $\frac{1}{4}$  

Step-by-step explanation:  

We are asked to find the probability of getting 3 heads on 4 flips.

$\text{Probability}=\frac{\text{Number of favorable outcomes}}{\text{Total number of possible outcomes}}$

Since we know that flipping a fair coin has 2 equally likely possible outcomes, so flipping four coins will have $2*2*2*2=16$ possible outcomes.

Sample space of possible outcomes.

HHHH, HHHT, HHTH, HHTT, HTHH, HTHT, HTTH, HTTT,

THHH, THHT, THTH,THTT, TTHH, TTHT, TTTH, TTTT.

We can see that there are 4 favorable outcomes of getting heads.

$\text{Probability of getting 3 heads}=\frac{4}{16}$

$\text{Probability of getting 3 heads}=\frac{1}{4}$

Therefore, the probability of getting 3 heads on 4 coins will be $\frac{1}{4}$ and option a is the correct choice.