Question

For the spinner above, the probability of landing on black is 1/2 and the probability of landing on red is 1/3. Suppose is is spun four times. What is the pobability that it will land on white all four times?
A. 1/216
B. 1/24
C. 1/4096
D. 1/1296


My answer was A. 1/216 but, that was wrong. Cant figure this out. I always hated doing probability questions...

Answer 1

Answer:

so you multiplied you answer one too few times.

The probability of recieving white on one run is 1/6, and you need the probability of four runs, so you need 1/6⁴ or 1/1296

Answer 2

First, we need to figure out the probability of landing on white one time. The probability of landing on black is 1/2, and the probability of landing on red is 1/3. If we add these probabilities together we get:

$\frac{1}{2}+ \frac{1}{3} = \frac{3}{6}+ \frac{2}{6} = \frac{5}{6}$

So if there is a 5/6 chance of NOT landing on white, then there must be a 1/6 chance of landing on white.

To find the probability of landing on white 4 times, multiply 1/6 to itself 4 times.

$( \frac{1}{6})^4 = \frac{1}{1296}$

The answer is D.