One jet left Detroit at 6:30 a.m. flying south at 410 mph, and another left at 8:30 a.m. flying south at 620 mph. How many hours will it take the second jet to catch up to the first? Round to the nearest tenth if necessary.

Question

One jet left Detroit at 6:30 a.m. flying south at 410 mph, and another left at 8:30 a.m. flying south at 620 mph.  How many hours will it take the second jet to catch up to the first? Round to the nearest tenth if necessary.

hartnn · Answer

u know the formula speed=distance/time
here distances traveled are equal so equate the product of speed and time for both....

anonymous · Answer

how do i equate the distance?

hartnn · Answer

sorry,
u have the speed,u just need time for both planes now...
then u can equate product of spped and time for both planes...

anonymous · Answer

whats the answer then?

anonymous · Answer

r t = d
Let t be the time the second jet takes to overtake the first.  Then:
410 (t + 2) = 620 t
t = 82/21=3.90476 or 3.9 hours to the nearest tenth

anonymous · Answer

Thank you for the medal, @reonrobe.