Which situation is linear?

A: A sample of bacteria is doubling every day

B: the number of cars each hour on a road for a week

C: the cost of a movie ticket increases five percent each year

D: the population of a town in increasing by ten people each year

Question

Which situation is linear?

A: A sample of bacteria is doubling every day

B: the number of cars each hour on a road for a week

C: the cost of a movie ticket increases five percent each year

D: the population of a town in increasing by ten people each year

whpalmer4 · Answer

It will be linear if it can be represented by a straight line, or put in the form $$y=mx+b$$Which of those situations changes by a fixed amount per interval?

penguin1234 · Answer

Guessing A

penguin1234 · Answer

Not Sure

whpalmer4 · Answer

It pains me when I tell you exactly how to recognize the answer, and yet you choose to guess :-(

If a sample of bacteria doubles every day, does it add the same number of bacteria each day?  First day there is 1, second day there are 2 (adding 1), third day there are 4 (adding 2), fourth day there are 8 (adding 4), etc.  Does that sound like it changes by a fixed amount each interval?

whpalmer4 · Answer

B is no good either, as we have no idea what the number of cars on the road is, so how could we possibly judge whether or not it is linear?

That leaves C and D.  I urge you to think carefully about which one is a straight line when graphed, and which one is not.