Question

A spinner has an equal chance of landing on either red blue or green. You spin six times. What is the probability that spinner lands on red at least two times?

Answer 1

0.8906 ( 4 decimal places)

Explanation:

With an equal probability of landing in either blue or red, then

Probability of success, p = 0.5

Number of trials, n = 6

Probability of landing on red atleast twice Can be obtained using a cumulative binomial probability ;

P(x =x) = nCx * p^x * (1 - p)^(n - x)

P(x ≥ 2) = p(x = 2) + p(x = 3) + p(x = 4) + p(x = 5) + p(x = 6)

Obtaining the individual probabilities and summing them up or we could use a cumulative probability option on either a calculator, excel or an online binomial probability distribution.

Using an online binomial probability calculator :

P(x ≥ 2) = 0.890625

P(x ≥ 2) = 0.8906 ( 4 decimal places)