Difficulty: Easy
Correct Answer: 1/5
Explanation:
Introduction / Context:
This question tests the slope formula for a line passing through two given points. Slope measures the rate of change of y with respect to x and is computed as “rise over run.” In coordinate geometry and aptitude, accurately substituting into the slope formula is essential, and simplifying the resulting fraction correctly is a common requirement.
Given Data / Assumptions:
Concept / Approach:
Use the slope formula:
m = (y2 - y1) / (x2 - x1).
Any consistent order works as long as you subtract y and x in the same order. Then simplify the fraction. The sign of the slope indicates whether the line rises or falls as x increases.
Step-by-Step Solution:
1) Identify (x1, y1) = (8, 2) and (x2, y2) = (3, 1)
2) Apply the slope formula:
m = (y2 - y1) / (x2 - x1)
3) Substitute values:
m = (1 - 2) / (3 - 8)
4) Compute differences:
1 - 2 = -1
3 - 8 = -5
5) Divide:
m = (-1)/(-5) = 1/5
Verification / Alternative check:
A quick interpretation check: moving from x = 3 to x = 8 increases x by 5 while y increases from 1 to 2, which is an increase of 1. So rise/run = 1/5, matching the computed slope. The slope is positive, which makes sense because y increases as x increases across these two points.
Why Other Options Are Wrong:
• 5 is the reciprocal (run/rise) and not the slope.
• 3/5 and 5/3 come from incorrect subtraction or mixing points.
• -1/5 would happen if only one difference is made negative (inconsistent subtraction).
Common Pitfalls:
• Subtracting y values in one order and x values in the opposite order.
• Forgetting that negative divided by negative becomes positive.
Final Answer:
1/5
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