To solve these probability questions, we need to use basic probability principles.
For question 24:
We are given the probabilities of stopping at different numbers of red lights. To find the probability of stopping at least two red lights, we need to calculate the sum of the probabilities of stopping at 2, 3, 4, and 5 red lights.
Probability of stopping at 2 red lights = 0.30
Probability of stopping at 3 red lights = 0.12
Probability of stopping at 4 red lights = 0.06
Probability of stopping at 5 red lights = 0.02
Sum of these probabilities = 0.30 + 0.12 + 0.06 + 0.02 = 0.50
So, the probability of stopping at least two red lights is 0.50. Therefore, the correct answer is (c) 0.50.
For question 25:
We are given the percentages of shoppers using different methods of shopping. To find the probability of a randomly selected shopper using at least one method of shopping, we need to subtract the percentage of shoppers who do not use any method from 1.
Percentage of shoppers using online shopping = 22%
Percentage of shoppers using malls and discount outlets = 45%
Percentage of shoppers using both methods = 15%
Percentage of shoppers not using any method = 100% - (22% + 45% - 15%) = 100% - 62% = 38%
So, the probability of a randomly selected shopper using at least one method of shopping is 1 - 0.38 = 0.62. Therefore, the correct answer is (c) 0.60.