A student scored 80, 85, 90, and 95 in four subjects. What score does he need in

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Question: A student scored 80, 85, 90, and 95 in four subjects. What score does he need in the fifth subject to achieve an average of 90?

Options:

Correct Answer: 100

Solution:

Mean = (80 + 85 + 90 + 95 + x) / 5 = 90. Solving gives x = 100.

A student scored 80, 85, 90, and 95 in four subjects. What score does he need in the fifth subject to achieve an average of 90?

A student scored 80, 85, 90, and 95 in four subjects. What score does he need in the fifth subject to achieve an average of 90?

Step 1: Add the scores of the first four subjects: 80 + 85 + 90 + 95.
Step 2: Calculate the total from Step 1: 80 + 85 + 90 + 95 = 350.
Step 3: Let 'x' be the score needed in the fifth subject.
Step 4: Write the formula for the average: (350 + x) / 5 = 90.
Step 5: Multiply both sides of the equation by 5 to eliminate the fraction: 350 + x = 450.
Step 6: Subtract 350 from both sides to solve for 'x': x = 450 - 350.
Step 7: Calculate the value of 'x': x = 100.

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