Question

If one ticket is randomly selected from tickets numbered 1-30 then find the probability that the number on the ticket is a multiple of 3 or 5?

Answer 1

Step 1: Count the number of tickets that are multiples of 3 or 5.
Multiples of 3: There are $\frac{30}{3}$ = 10 tickets that are multiples of 3 (1, 3, 6, 9, 12, 15, 18, 21, 24, 27).
Multiples of 5: There are $\frac{30}{5}$ = 6 tickets that are multiples of 5 (5, 10, 15, 20, 25, 30).
However, we have counted the number 15 twice because it is both a multiple of 3 and 5. So, we need to subtract one from the total count.
Total count of tickets that are multiples of 3 or 5 = 10 + 6 - 1 = 15.
Step 2: Calculate the probability.
The total number of tickets is 30.
Probability = Count of favorable outcomes / Total count of outcomes
Probability = $\frac{15}{30}$ = 1/2 = 0.5
Therefore, the probability that the number on the randomly selected ticket is a multiple of 3 or 5 is 0.5 or 50%.