Question

The time t required to drive a certain distance varies inversely with the speed r. If it takes 2 hours to drive the distance at 67 miles per hour, how long will it take to drive the same distance at 55 miles per hour?
A. About 1.64 hours
B. About 134 hours
C. About 2.45 hours
D. About 61 hours

Answer 1

We are given:

The time t required to drive a certain distance varies inversely with the speed r.

According to the question t is inversely proportional to speed(r).

let us say distance (d) is constant of proportionality,

So the equation becomes,

$t=\frac{d}{r}$

Now from the question, we are given it takes 2 hours to drive the distance at 67 miles per hour, so plugging these in the above equation,

$2=\frac{d}{67}$

d=134 miles.

Now we have to find how long will it take to drive the same distance that is 134 miles at 55 miles per hour

so plugging the values, we have,

$t=\frac{134}{55}$

t=2.436

So the time taken will be around 2.5 hours.

Answer :  It will take about 2.5 hours to drive the same distance at 55 miles per hour. Option C. About 2.5 hours.

Answer 2

C........................