Since 1 cm = 10 mm
Then 4 cm = 40 mm
So first start out by writing an expression for the cost of the child and the adult separately.
Child:
6 + 1r ($6 + $1 per ride)
Adult:
10 + 1.5r ($10 + $1.50 per ride)
to find how much more the adult will spend, just do Adult Expression - Child Expression which will be:
10 + 1.5r - (6 + 1r) just simplify this
For Part B, use your equation from part A where r = 7
Answer:

Step-by-step explanation:
The equation for a line is y=mx + b where m represents the slope
If a line is perpendicular to another line, it's slope is the negative reciprocal of the other line's slope.
The reciprocal of -4 is 
And the negative of that would be 