Title: Constant Rate of Change Pre-Video Questions
Course: Calculus Videos Project > Section: Constant Rate of Change

Q: Melissa is driving along a straight road from Dallas, Texas to Oklahoma City, Oklahoma at a constant velocity. Every increase of ten minutes in the number of minutes x since passing the state line, her distance y from Oklahoma City decreases by seven miles.

Which of the following statements is definitely true? (Note: Δy can be read as “change in y” and Δx as “change in x.”
- ∆y = –0.7∆x
- y = –0.7x
- x = –0.7y
- ∆x = –0.7∆y
- Only statements (a) and (b) are definitely true.
- Only statements (c) and (d) are definitely true.
A: ∆y = –0.7∆x

Q: A candle has been burning at a constant rate of change of 1.25 inches per hour. The candle has been burning for 4 hours and is 5.5 inches tall. What was the length of the candle before it was lit?
- 5 inches
- 5.5 inches
- 6.75 inches
- 10.5 inches
- 23.25 inches
A: 10.5 inches