It could be a box plot or a Histogram
Step-by-step explanation:

Hope it will help :)
4/5x-2>3/10*2x
4/5x-2>3/5x (3/10*2=3/5)
-2>-1/5x (subtract the 4/5x)
10<x (divide by -1/5 and change sign)
There are 150 9th graders and 300 10th graders
R = speed in still water
r + c = speed with current
r - c = speed against current
3.5(r + c) = 70
r + c = 20
c = 20 - r
4(r + c) = distance from pier to pier
5(r - c) = distance from pier to pier
4(r + c) = 5(r - c)
4(r + 20 - r) = 5(r - 20 + r)
80 = 10r - 100
180 = 10r
18 = r
The speed in still water is 18 km/hour