If (A(t)=240-11t) and (B(t)=60+4t), when will (A(t)) be (15) more than (B(t))?
Answer and explanation
Correct answer: \(t=11\)
“15 more” means \(A(t)=B(t)+15\). Thus, \(240-11t=60+4t+15\), which gives \(165=15t\) and hence \(t=11\). Therefore, option C is correct. At \(t=10\), the difference is \(30\), not 15. Exam tip: For “more than” questions, write the larger quantity as the smaller quantity plus the stated difference.
Frequently asked questions
What is the correct answer to this question?
\(t=11\)
Why is this the correct answer?
“15 more” means \(A(t)=B(t)+15\). Thus, \(240-11t=60+4t+15\), which gives \(165=15t\) and hence \(t=11\). Therefore, option C is correct. At \(t=10\), the difference is \(30\), not 15. Exam tip: For “more than” questions, write the larger quantity as the smaller quantity plus the stated difference.
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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