60 subs
Because it’s 15 per 45 and 45 times 4 is 180 which means that in 3 hours or 180 minutes they sold 15 times 4 amount of subs and 15 times four is 60. Hope this helps. Sorry if the explanation isn’t that good
For it to be a linear equation, the same difference in x must produce the same difference in y always.
Choice A.
difference in x: 2 - 1 = 1
difference in y: -6 - (-2) = -4
difference in x: 3 - 2 = 1
difference in y: -2 - (-6) = 4
A difference of 1 in x gave a difference of -4 in y and another difference of 1 in x gave a difference of 4 in y.
This is not linear.
Choice B.
difference in x: 2 - 1 = 1
difference in y: -5 - (-2) = -3
difference in x: 3 - 2 = 1
difference in y: -9 - (-5) = -4
A difference of 1 in x gave a difference of -3 in y and another difference of 1 in x gave a difference of -4 in y.
This is not linear.
Choice C.
difference in x: 2 - 1 = 1
difference in y: -10 - (-2) = -8
difference in x: 3 - 2 = 1
difference in y: -18 - (-10) = -8
Do the other differences. All differences in y are -8 corresponding to a difference in x of -1.
This is linear.
Choice D.
The differences in y vary. It is not linear.
Answer: Choice C is linear.
