The mean of three numbers is 30. If one of the numbers is 20, what is the mean of the other two numbers? (2023)

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Q: The mean of three numbers is 30. If one of the numbers is 20, what is the mean of the other two numbers? (2023)

Solution: Let the three numbers be a, b, c. Then, (a + b + 20) / 3 = 30. Thus, a + b = 90, and the mean of a and b = 90 / 2 = 45.

Steps: 6

Step 1: Understand that the mean (average) of three numbers is given as 30.
Step 2: Recall that the mean is calculated by adding all the numbers together and dividing by the total count of numbers.
Step 3: Set up the equation for the mean: (a + b + 20) / 3 = 30, where a and b are the other two numbers.
Step 4: Multiply both sides of the equation by 3 to eliminate the fraction: a + b + 20 = 90.
Step 5: Subtract 20 from both sides to find the sum of a and b: a + b = 90 - 20 = 70.
Step 6: Now, to find the mean of a and b, divide their sum by 2: (a + b) / 2 = 70 / 2 = 35.