A student flips a coin four times. What is the probability the coin lands tails up exactly three times?

The probability is

a

.

0.25

Step-by-step explanation:

Use binomial probability:

P = nCr pʳ qⁿ⁻ʳ

where n is the number of trials,

r is the number of successes,

p is the probability of success,

and q is the probability of failure (1-p).

P = ₄C₃ (0.5) ³ (1-0.5) ⁴⁻³

P = 4 (0.5) ³ (0.5)

P = 0.25