Question

please help on this one?

Answer 1

Since the x axis represents the number of pen bought and the y axis the number of notebook, the total cost will be 2x+3y, because each pen costs 2$ and each notebook 3$.

You want this quantity to be no more than 30, so you must ask

$2x+3y \leq 30$

which means that the shaded area must be under the graph of the line

$2x+3y = 30$

You can rewrite the equation as

$y = -\dfrac{2x}{3} + 10$

So, the y intercept is the point $(0,10)$

So the answer must be either C or D.

To find the x intercept, set y=0:

$0 = -\dfrac{2x}{3} + 10 \iff \dfrac{2x}{3} = 10 \iff 2x = 30 \iff x = 15$

So, the correct answer is D.