If (A(t)=a+9t) and (A(3)=57), what is (a)?
Answer and explanation
Correct answer: 30
Given \(A(t)=a+9t\), substitute \(t=3\): \(A(3)=a+9\times3=a+27\). Since \(A(3)=57\), we get \(a+27=57\), so \(a=30\). Option 27 is the amount added over 3 time units, not the initial value \(a\). Exam tip: substitute the specified value of \(t\) first, then solve the resulting equation.
Frequently asked questions
What is the correct answer to this question?
30
Why is this the correct answer?
Given \(A(t)=a+9t\), substitute \(t=3\): \(A(3)=a+9\times3=a+27\). Since \(A(3)=57\), we get \(a+27=57\), so \(a=30\). Option 27 is the amount added over 3 time units, not the initial value \(a\). Exam tip: substitute the specified value of \(t\) first, then solve the resulting equation.
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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