If (F(t)=20+rt) and (F(3)=41), what is (F(7))?
Answer and explanation
Correct answer: 69
Given \(F(t)=20+rt\) and \(F(3)=41\), we get \(20+3r=41\). Thus, \(3r=21\) and \(r=7\). Now \(F(7)=20+7\times7=69\). The value 62 would result from using an incorrect rate or value of \(t\). Exam tip: first find \(r\) from the given function value, then substitute the required \(t\).
Frequently asked questions
What is the correct answer to this question?
69
Why is this the correct answer?
Given \(F(t)=20+rt\) and \(F(3)=41\), we get \(20+3r=41\). Thus, \(3r=21\) and \(r=7\). Now \(F(7)=20+7\times7=69\). The value 62 would result from using an incorrect rate or value of \(t\). Exam tip: first find \(r\) from the given function value, then substitute the required \(t\).
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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