Question

PLEASE HELP QUICK!!
A truck drove at an average rate of 45 miles per hour on the highway and 20 miles per hour once it entered the city. If it took the trip, which was 100 miles, in 3 hours, how much of it was in the city?

Answer 1

Answer:

28 miles in 1.4 hours in the city

Step-by-step explanation:

On the highway:

Time $=t$ hours

Rate = 45 mph

Distance $=45\cdot t$ miles

In the city:

Time $=3-t$ hours

Rate = 20 mph

Distance $=20\cdot (3-t)$ miles

The trip was 100 miles long, then

$45t+20(3-t)=100\\ \\45t+60-20t=100\\ \\45t-20t=100-60\\ \\25t=40\\ \\t=1.6\ hours\\ \\3-t=3-1.6=1.4\ hours$

Distance on the highway $=45\cdot 1.6=72$ miles

Distance in the city $=20\cdot 1.4=28$ miles