A car travelling at 60km/hr left dehradun at 3pm. One hour later another car travelling at 80km/hr started over the same road to overtake the first. How long must the second car travel?
Please answer fast!!! Tomorrow exam!!!

Let the second car overtakes the first car,  x hours after it started.Now, time for which firt car travelled = x+1 hrsAlso ,distance covered by both the cars will be same when the second car overtakes the first car.Distance covered by first car in x+1 hrs = speed ×time = 60x+1 kmDistance covered by second car in x hrs = 80xNow, according to question60x+1 = 80x60x+60 = 80x80x - 60x = 6020x = 60x = 6020 = 3So, after 3 hours, second car overtakes the first car.

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let the time taken by 1st car be x hrs
then 60kmx=80km(x-1)
or 60kmx=80kmx-80km
​or -20kmx=-80km
or x=4
so the second car will travel 4-1=3hrs
 
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