The average of three numbers is 30. If one of the numbers is 10, what is the average of the other two numbers?
Practice Questions
1 question
Q1
The average of three numbers is 30. If one of the numbers is 10, what is the average of the other two numbers?
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30
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40
Let the three numbers be a, b, and c. We have (a + b + c) / 3 = 30. Thus, a + b + c = 90. If c = 10, then a + b = 90 - 10 = 80. The average of a and b is 80 / 2 = 40.
Questions & Step-by-step Solutions
1 item
Q
Q: The average of three numbers is 30. If one of the numbers is 10, what is the average of the other two numbers?
Solution: Let the three numbers be a, b, and c. We have (a + b + c) / 3 = 30. Thus, a + b + c = 90. If c = 10, then a + b = 90 - 10 = 80. The average of a and b is 80 / 2 = 40.
Steps: 9
Step 1: Understand that the average of three numbers is given as 30.
Step 2: Recall that the average is calculated by adding the numbers together and dividing by the total count of numbers.
Step 3: Set up the equation for the average: (a + b + c) / 3 = 30.
Step 4: Multiply both sides of the equation by 3 to eliminate the division: a + b + c = 90.
Step 5: Identify that one of the numbers, c, is 10.
Step 6: Substitute c with 10 in the equation: a + b + 10 = 90.
Step 7: Solve for a + b by subtracting 10 from both sides: a + b = 90 - 10 = 80.
Step 8: To find the average of the two numbers a and b, divide their sum by 2: (a + b) / 2 = 80 / 2.
