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If (y=30+kx) and (y=54) at (x=4), what is (k)?
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Answer and explanation
Correct answer: \(6\)
Given \(y=30+kx\), substitute \(x=4\) and \(y=54\): \(54=30+4k\). Thus, \(4k=24\), so \(k=6\). Option \(24\) is the value of \(4k\), not of \(k\). Exam tip: To find an unknown coefficient in a linear expression, substitute the given values of \(x\) and \(y\) first.
Frequently asked questions
What is the correct answer to this question?
\(6\)
Why is this the correct answer?
Given \(y=30+kx\), substitute \(x=4\) and \(y=54\): \(54=30+4k\). Thus, \(4k=24\), so \(k=6\). Option \(24\) is the value of \(4k\), not of \(k\). Exam tip: To find an unknown coefficient in a linear expression, substitute the given values of \(x\) and \(y\) first.
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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