Modelling with functions Quiz

1. What does $\theta=20+70\times0.9^t$ predict for the temperature as $t$ becomes very large?

• A. $0\,^\circ\text{C}$
• B. $90\,^\circ\text{C}$
• C. $20\,^\circ\text{C}$
• D. $70\,^\circ\text{C}$

2. In the cost model $C=450+0.2x$, what does the gradient represent?

• A. The cost per mile
• B. The fixed cost
• C. The total cost
• D. The number of miles

3. The model $h=1.5+12t-5t^2$ gives $h=-7.5$ at $t=3$. What does this show?

• A. The ball is $7.5$ m high
• B. The ball has already landed, so the model is not valid at $t=3$
• C. The ball is thrown downwards
• D. The model is exact

4. Which refinement best deals with a bacteria model that predicts unlimited growth?

• A. A larger growth factor
• B. A linear function
• C. Removing the initial value
• D. A function that levels off at a maximum

5. Using $N=200\times1.5^t$, find $N$ when $t=3$.

• A. $600$
• B. $675$
• C. $900$
• D. $1000$