# The task is to make up an exam style question of your choice worth 7 marks on algebra in context. And to create your own mark scheme on it.You can also highlight potential mistakes people answering...

**The task is to make up an exam style question of your choice worth 7 marks on algebra in context. And to create your own mark scheme on it.**

You can also highlight potential mistakes people answering the question may make therefore add tips and hints and it must be for top/high level stundents.

Thanks

*print*Print*list*Cite

### 1 Answer

Question:

Amanda plants a sunflower seed. After 10 days, a small sprout appears and begins to grow steadily. On day 18, the plant has reached a height of 16 cm.

a) Predict the height of the plant on day 24 using any method. Show work.

b) Graph the data, then write an equation in the form y = mx + b to represent the height of the plant on day x after the seed was planted.

c) Use your equation to predict the height of the plant on day 60.

d) What factors might affect the accuracy of your prediction?

--------------

a) Students should notice that the plant grows 16cm in 8 days. They could use several methods to predict the height on day 24, but should come up with 28cm. I would award 2 points here, one for developing a reasonable technique and one for finding 28cm. (+2)

b) Accurate graph should be worth a point (consider providing axes for the students, depending on what you're trying to assess). Students should see that the y-intercept is -20, and the slope is 2 (2 more points for the answer: y = 2x-20) (+3)

c) 100cm. But if the equation was incorrect, it will affect this answer. If the result is consistent with the equation, I award the point. (+1)

d) Plant might not grow at a steady rate (eventually the sunflower will slow down and reach a constant height, so the linear approximation will fail after awhile). (+1)