Question

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

The probability is
a
.

Answer 1

0.25

Explanation:

Answer 2

0.25

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