Question

Use the complementary rule to solve the following problem: A spinner has 4 equal sectors colored yellow, blue, green and red. What is the probability of landing on a sector that is not red after spinning this spinner? Remember, the complementary rule states that the probability that something does not occur is = 1 minus the probability that it does occur.

Answer 1

A spinner has 4 equal sectors colored yellow, blue, green and red.

Probability of landing on any sector after spinning = 1/4  

( Since there are 4 equal sectors and each of them is having the equal chance of landing after spinning)

so, Probability of landing on a sector that is red= 1/4

using complementary rule : Probability that something does not occur = 1 - probability that it does occur

Hence, Probability of landing on a sector that is not red =  1 - Probability of landing on a sector that is red

=1 - 1/4

= 3/4