If water in a tank is (W(t)=75-5t) litres, what type of change is it?
Answer and explanation
Correct answer: Linear decay
Here, W(t)=75-5t is a linear expression because the power of t is 1. The coefficient of t is -5, so the amount of water decreases by 5 litres for every 1-unit increase in t. Therefore, it represents linear decay. A constant amount would have no t-term, while in exponential change the variable appears in the exponent. Exam tip: in the linear form at+b, a negative value of a indicates decay.
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What is the correct answer to this question?
Linear decay
Why is this the correct answer?
Here, W(t)=75-5t is a linear expression because the power of t is 1. The coefficient of t is -5, so the amount of water decreases by 5 litres for every 1-unit increase in t. Therefore, it represents linear decay. A constant amount would have no t-term, while in exponential change the variable appears in the exponent. Exam tip: in the linear form at+b, a negative value of a indicates decay.
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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