If \(y=95-5x\) and \(x\) changes from \(4\) to \(11\), what is the total decrease in \(y\)?
Answer and explanation
Correct answer: \(35\)
The change in \(x\) is \(11-4=7\). The coefficient of \(x\) is \(-5\), so for every increase of 1 in \(x\), \(y\) decreases by 5. Hence, the total decrease in \(y\) is \(5\times 7=35\). Equivalently, \(y(4)=75\) and \(y(11)=40\), so the decrease is \(75-40=35\). Exam tip: multiply the magnitude of the coefficient by the change in the variable to find total decrease.
Frequently asked questions
What is the correct answer to this question?
\(35\)
Why is this the correct answer?
The change in \(x\) is \(11-4=7\). The coefficient of \(x\) is \(-5\), so for every increase of 1 in \(x\), \(y\) decreases by 5. Hence, the total decrease in \(y\) is \(5\times 7=35\). Equivalently, \(y(4)=75\) and \(y(11)=40\), so the decrease is \(75-40=35\). Exam tip: multiply the magnitude of the coefficient by the change in the variable to find total decrease.
Which subject and chapter does this question cover?
This is a Class 9 Mathematics question. Chapter: Introduction to Polynomials. Topic: Linear growth and decay.
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