Question

3. A family is tracking its spending habits. Over the past year, the grocery bill has ranged from $110 to $170. Suppose you were going to plot these points on a coordinate grid.

(a) What is a good scale to use for the y-axis? Explain your reasoning.
(b) What is a good interval to use for the y-axis? Explain your reasoning.

Answer 1

The best way to plot them is by month.
170-110 =$60.
As, we are supposed to plot in months and the above calculation is in year, convert it into months
60/5 = $5 each month
So, the coordinates would be 0,110 1,115 2,120 3,125
and you x will be the month
and your money will be the Y axis

Answer 2

Answer: a) 1 scale = 10 units

b) Interval = 10 units.

Explanation:

Since we have given that

Range of the grocery bill = from 110 to 170

Suppose we want to plot these points on a coordinate grid.

a) What is a good scale to use for the y-axis?

Good scale must of 10 units i.e.

1 scale = 10 units

As 110 and 170 has 10 as a highest common factor (HCF)

(b) What is a good interval to use for the y-axis?

Good Interval must be of 10 units too.

i.e. 110-120, 120-130, 130-140, 140-150, 150-160, 160-170.

Hence, a) 1 scale = 10 units

b) Interval = 10 units.