If distance left is (D(t)=120-15t) km, how much distance will be left at (t=4)?
Answer and explanation
Correct answer: 60 km
Given \(D(t)=120-15t\). Substituting \(t=4\), \(D(4)=120-15\times4=120-60=60\) km. Hence, 60 km of distance is left after 4 time units. The value 75 km would result from using \(t=3\), not \(t=4\). Exam tip: Substitute the given value of \(t\) in every term of the linear expression carefully.
Frequently asked questions
What is the correct answer to this question?
60 km
Why is this the correct answer?
Given \(D(t)=120-15t\). Substituting \(t=4\), \(D(4)=120-15\times4=120-60=60\) km. Hence, 60 km of distance is left after 4 time units. The value 75 km would result from using \(t=3\), not \(t=4\). Exam tip: Substitute the given value of \(t\) in every term of the linear expression carefully.
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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