If R(t) = 40 - 6t, by how much will R(t) decrease when t increases by 1?
Answer and explanation
Correct answer: 6
In a linear rule R(t)=a+bt, the coefficient b gives the change in R for each increase of 1 in t. Here b=-6, so R decreases by 6 units whenever t increases by 1. Directly, R(t+1)-R(t)=[40-6(t+1)]-[40-6t]=-6, confirming a decrease of 6. Thus option A is correct; 40 is the initial value, not the change.
Frequently asked questions
What is the correct answer to this question?
6
Why is this the correct answer?
In a linear rule R(t)=a+bt, the coefficient b gives the change in R for each increase of 1 in t. Here b=-6, so R decreases by 6 units whenever t increases by 1. Directly, R(t+1)-R(t)=[40-6(t+1)]-[40-6t]=-6, confirming a decrease of 6. Thus option A is correct; 40 is the initial value, not the change.
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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