The only rule to follow is
Divide dividend by divisor and the mention the quotient and things left after remains in place of remainder
Here is a sample

Answer: 343.6875 US$
Step-by-step explanation:
(US$ 9.75) x (35 1/4) =
Hello!
Your answer is the second option.
Hope this helps!
You would need more details like the y values or something. Rate of change is slope though if that helps you enough to figure it out
Answer:
The actual length of the lap = 250 meters
Step-by-step explanation:
∵ The scale factor of the map is 1:1000
∵ The length of the lap on the map is 25 cm
∴ 
Where x is the actual length of a lap
∴ x = (25 × 1000) ÷ 1 = 25000 cm
∵ 1 meter = 100 centimeter
∴ The actual length of the lap = 25000 ÷ 100 = 250 meters