In the line \(y=-\frac{2}{5}x+3\), how much will (y) decrease when (x) increases by (10)?
Answer and explanation
Correct answer: 4
The slope is \(-\frac{2}{5}\), so for every increase of 5 units in \(x\), \(y\) decreases by 2 units. For an increase of 10 units, \(\Delta y=-\frac{2}{5}\times 10=-4\). Hence, \(y\) decreases by 4 units. Option 2 would apply only when \(x\) increases by 5 units. Exam tip: when asked “how much does it decrease,” report the magnitude of the negative change.
Frequently asked questions
What is the correct answer to this question?
4
Why is this the correct answer?
The slope is \(-\frac{2}{5}\), so for every increase of 5 units in \(x\), \(y\) decreases by 2 units. For an increase of 10 units, \(\Delta y=-\frac{2}{5}\times 10=-4\). Hence, \(y\) decreases by 4 units. Option 2 would apply only when \(x\) increases by 5 units. Exam tip: when asked “how much does it decrease,” report the magnitude of the negative change.
Which subject and chapter does this question cover?
This is a Class 9 Mathematics question. Chapter: Introduction to Polynomials. Topic: Slope and y-intercept.
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