Joan left Durham traveling 85 mph. Mike,to catch up,left some time later driving at 94 mph. Mike caught up after 7 hours. How long was Joan driving before Mike caught up?

1 Answer
Apr 26, 2018

Joan had been driving for 7hours 44mins

Explanation:

*Before we start we should immediately note that "speed, distance and time" are all present in the question. Therefore we know we will most likely need to use the equation: "Speed"="Distance"/"Time"

Firstly let's call the place where the two people meet x.

To get to point x Joan travelled at 85mph for y amount of time.

To get to point x Mike travelled at 94mph for 7 hours.

Mike has given us both "speed and time" We can, therefore, now work out the distance Mike meets Joan.
-Rearrange the formula :"Distance"="Speed" times "Time"

"Distance"=94 times 7

"Distance"=658"miles"

We now know that the point they both meet at (which we called x to start with is: 658

We now know the "Distance and Speed" of Joan. We can, therefore, work out the length of time Joan has been travelling.
-Rearrange the formula: "Time"="Distance"/"Speed"
"Time"=658/85

"Time"=7.74"hours"(2.D.P.)

Now all that remains for us to do is work out how many minutes Joan has been travelling for.

"mins"/60 times 100=74

"mins"/60=74/100

"mins"=74/100 times 60

"mins"=44

Joan has therefore been travelling for 7hours 44mins