If the scores of 5 students are 10, 20, 30, 40, and x, and the mean is 30, what

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Question: If the scores of 5 students are 10, 20, 30, 40, and x, and the mean is 30, what is the value of x?

Options:

Correct Answer: 50

Solution:

Mean = (10 + 20 + 30 + 40 + x) / 5 = 30. Solving gives x = 50.

If the scores of 5 students are 10, 20, 30, 40, and x, and the mean is 30, what is the value of x?

If the scores of 5 students are 10, 20, 30, 40, and x, and the mean is 30, what is the value of x?

Step 1: Write down the scores of the 5 students: 10, 20, 30, 40, and x.
Step 2: Understand that the mean (average) is calculated by adding all the scores together and then dividing by the number of scores.
Step 3: Set up the equation for the mean: (10 + 20 + 30 + 40 + x) / 5 = 30.
Step 4: Calculate the sum of the known scores: 10 + 20 + 30 + 40 = 100.
Step 5: Substitute the sum into the equation: (100 + x) / 5 = 30.
Step 6: Multiply both sides of the equation by 5 to eliminate the fraction: 100 + x = 150.
Step 7: Solve for x by subtracting 100 from both sides: x = 150 - 100.
Step 8: Calculate the value of x: x = 50.

Mean Calculation – Understanding how to calculate the mean (average) of a set of numbers.
Algebraic Manipulation – Solving for an unknown variable in an equation.