Final answer:
The mean of the five original numbers is 30.
Step-by-step explanation:
To find the mean of the original five numbers, we need to find the sum of the five original numbers. Let's assume the original five numbers are a, b, c, d, and e. We know that when each of the five numbers is doubled, the mean of the five new numbers is 60. This means that the sum of the five new numbers is 5 * 60 = 300. Since each number is doubled, the sum of the five original numbers is half of the sum of the five new numbers, which is 300 / 2 = 150. Therefore, the mean of the five original numbers is the sum divided by 5, which is 150 / 5 = 30.
To find the mean of the original numbers, we can reverse the operation of doubling. If doubling each number results in a mean of 60, then the original mean must be half of 60.
Therefore, the original mean is 60 ÷ 2 = 30. So the correct option is: (b) 30.