Answer : 123.
Step-by-step explanation :
To find the mean of a set of numbers, you add up all the numbers in the set and then divide by the total count of numbers.
Here's the step-by-step process:
1. Add up all the numbers: (120 + 118 + 120 + 136 + 121 = 615).
2. Count the total numbers in the set: There are 5 numbers in the set.
3. Divide the sum by the total count: (615 \ 5 = 123).
Therefore, the mean of the numbers 120, 118, 120, 136, and 121 is 123.
