Two planes travel toward each other from cities that are about 450 km apart at rates of 240 km/hr and 210 km/hr. they started at the same time. in how many hours will they meet?

t = 1 hour

Step-by-step explanation:

Oddly the distances add. Each plane will contribute a certain distance to make the 450 km. They will meet after the same number of hours have passed.

d = r * t

r1 = 240 km/hour

t1 = t

r2 = 210 km/hour

t2 = t

240*t + 210*t = 450     collect the terms on the left.

450t = 450                   divide by 450

450t/450 = 450/450

t =1

After 1 hour they will meet.

last one.

step-by-step explanation:

last one.

generally speaking, the others follow some sort of pattern that correlates to either linear (looks like a straight line) or sinusoidal (looks like an s).

the last one is just a random cloud of points that doesn't correlate to any particular known order.