Mathematics

Problem

Three carts P, Q, and R travel along the same straight track. Their positions as functions of time are described by the following equations, where

t

is in seconds and

x

in meters: • Cart P:

x = 2t + 1

• Cart Q:

x = 0.50t^{2}

• Cart R:

x = -3t + 5

t = 4\,\text{s}

, which of the following ranks the instantaneous speeds of the carts from greatest to least? a)

R > P > Q

Q > P > R

Q > R > P

R > Q > P