Which situation can be modeled by a linear function?

(1) The population of bacteria triples every day.

(2) The value of a cell phone depreciates at a rate of 3.5% each year.

(3) An amusement park allows 50 people to enter every 30 minutes.

(4) A baseball tournament eliminates half of the teams after each

round.

Here is their argument. given the obtuse angle x, we make a quadrilateral abcd with ∠dab = x, and ∠abc = 90◦, and ad = bc. say the perpendicular bisector to dc meets the perpendicular bisector to ab at p. then pa = pb and pc = pd. so the triangles pad and pbc have equal sides and are congruent. thus ∠pad = ∠pbc. but pab is isosceles, hence ∠pab = ∠pba. subtracting, gives x = ∠pad−∠pab = ∠pbc −∠pba = 90◦. this is a preposterous conclusion – just where is the mistake in the "proof" and why does the argument break down there?

Acar traveling at 65 mph leaves 25 foot skid mark what is the ratio of the speed to length of skid mark (feet) in the simplest form

The rows and columns of lattice points in a three-by-three square array are evenly spaced one unit apart. how many distinct triangles with at least one side of length 2 units can be drawn using three lattice points for the vertices?