Question

A few years ago, the legal speed limit on the Turner Turnpike between Tulsa and Oklahoma City was changed from 55.0 mi/h to 75.0 mi/h. How much time was saved on the 86.0 mile trip for someone traveling at the legal speed limit? May I have help solving this?

Answer 1

Given

Speed one:

v1 = 55 mi/h

Speed two:

v2 = 75 mi/h

Distance:

x = 86 mi

Procedure

Let's calculate the times for each of the speeds.

`\begin{gathered} t_1=(x)/(v_1) \\ t_1=(86mi)/(55mi/h) \\ t_1=1.56h \end{gathered}`
`\begin{gathered} t_2=(86mi)/(75mi/h) \\ t2=1.14h \end{gathered}`

Saving time:

`\begin{gathered} t_s=t_1-t_2 \\ t_s=1.56h-1.14h \\ t_s=0.42h \end{gathered}`

The total time saved is 0.42h (25.2min) by increasing the speed limit.