Suppose the velocity of an automobile starting from rest is given by
$$\mathrm{v}=\frac{200 \mathrm{t}}{2 \mathrm{t}+10}$$
Where $v$ is the velocity in miles per hour and $t$ is the time in seconds. Find the number of seconds when the velocity is 50 miles per hour.
A) $6 \mathrm{sec}$
B) $5 \mathrm{sec}$
C) $7 \mathrm{sec}$
D) $2.5 \mathrm{sec}$

Question

Quizplus · Accepted Answer

To find the time when the velocity is 50 mph, set $v = 50$ and solve for $t$:  $$50 = \frac{200t}{2t + 10}$$  Cross-multiply to get:  $$50(2t + 10) = 200t$$  $$100t + 500 = 200t$$  $$500 = 100t$$  $$t = 5$$ seconds.

Suppose the Velocity of an Automobile Starting from Rest Is v=200t2t+10\mathrm{v}=\frac{200 \mathrm{t}}{2 \mathrm{t}+10}v=2t+10200t​

Suppose the Velocity of an Automobile Starting from Rest Is $\mathrm{v}=\frac{200 \mathrm{t}}{2 \mathrm{t}+10}$