IDNLearn.com is your go-to platform for finding accurate and reliable answers. Discover reliable answers to your questions with our extensive database of expert knowledge.

Two trains leave a train station travelling on parallel and adjacent tracks. Train A is traveling due north at a constant speed of 76 miles per hour. Train B is traveling due south at a constant speed of 44 miles per hour. If both trains leave the station at the same time, in approximately how many minutes will the trains be 22 miles apart?

Sagot :

let's recall that d = rt, or namely distance = rate * time, the time being in a unit "in the rate".

Train A is moving North with 76m/h, Train B is going South at 44 m/h, both taking off in opposite direction at the same time, hmmmm so at some point the distance covered by both will be 22 miles, let's say that happens at the "h" hour.

If at "h" hour A has covered say distance "d" miles, then we can say that B has covered "22 - d" miles or namely the slack from 22, let's make a table with all that

[tex]\begin{array}{lcccl} &\stackrel{miles}{distance}&\stackrel{mph}{rate}&\stackrel{hours}{time}\\ \cline{2-4}&\\ A&d&76&h\\ B&22-d&44&h \end{array}\qquad \implies \qquad \begin{cases} d = 76h\\ 22-d=44h \end{cases}[/tex]

[tex]\stackrel{\textit{substituting on the 2nd equation}}{22-(76h)=44h}\implies 22=120h\implies \cfrac{22}{120}=h\implies \cfrac{11}{60}=\underset{hrs}{h} \\\\[-0.35em] ~\dotfill\\\\ ~\hfill \stackrel{\textit{converting the hours to minutes}}{\cfrac{11}{60}\cdot 60\implies \underset{mins}{11}}~\hfill[/tex]