A student scores 80, 85, and 90 in three subjects. If he wants an average of 85,

₹0.0

Question: A student scores 80, 85, and 90 in three subjects. If he wants an average of 85, what score does he need in the fourth subject?

Options:

Correct Answer: 85

Solution:

Let the fourth score be x. (80 + 85 + 90 + x) / 4 = 85. Therefore, 255 + x = 340, so x = 85.

A student scores 80, 85, and 90 in three subjects. If he wants an average of 85, what score does he need in the fourth subject?

A student scores 80, 85, and 90 in three subjects. If he wants an average of 85, what score does he need in the fourth subject?

Step 1: Identify the scores the student has: 80, 85, and 90.
Step 2: Add these scores together: 80 + 85 + 90 = 255.
Step 3: Let the score the student needs in the fourth subject be represented as 'x'.
Step 4: To find the average of four subjects, use the formula: (total score) / (number of subjects).
Step 5: Set up the equation for the average: (255 + x) / 4 = 85.
Step 6: Multiply both sides of the equation by 4 to eliminate the fraction: 255 + x = 340.
Step 7: Solve for 'x' by subtracting 255 from both sides: x = 340 - 255.
Step 8: Calculate the value of 'x': x = 85.

Average Calculation – Understanding how to calculate the average of a set of numbers and how to manipulate equations to find an unknown value.
Algebraic Manipulation – Using algebra to solve for an unknown variable in an equation.