A "Local" train leaves a station and runs at an average rate of 35 mph. An hour and a half later an "Express" train leaves the station and travels at an average rate of 56 mph on a parallel track. How many hours after it starts will the Express overtake the Local?

{ hrs.}

Question

A "Local" train leaves a station and runs at an average rate of 35 mph. An hour and a half later an "Express" train leaves the station and travels at an average rate of 56 mph on a parallel track. How many hours after it starts will the Express overtake the Local?

{  hrs.}

anonymous · Answer

the local has gone $17.5$ miles in half an hour, when the express train leaves
since distance is rate times time, we know the distance the express travels will be $56t$ (if we use $t$ for time) and the distance the local travels will be $17.5+35t$ for the same time

anonymous · Answer

when they meet they will have travelled the same distance, so you can set them equal 
$$17.5+35t=56t$$ and solve for $t$

anonymous · Answer

subtract $35t$ from both sides gives you $17.5=21t$ divide by $21$ and get 
$$t=\frac{17.5}{21}$$ whatever that is

anonymous · Answer

oooh no i am sorry i don't know  how to read!!

anonymous · Answer

it says "one hour and a half" not "half an hour" no matter we can fix it

anonymous · Answer

in one and a half hours the local travelled $52.5$ miles set 
$$52.5+35t=56t$$

anonymous · Answer

same idea, different number 
$$21t=52.5$$
$$t=\frac{25.5}{21}$$ sorry