Question

At noon a car leaves Washington, D.C., headed for Miami, Florida, a distance of 1100 miles. The train travels at a speed of 60 mph. At 1 pm a second car leaves Miami headed for Washington D.C., traveling at 70 mph. At what time will the two trains pass each other?

Answer 1

I car starts at 12.00 noon

Distance between Washington and Miami = 1100 miles

Speed = 60 mph

Hence after 1 hour, I car will be at 60 miles from Washingon or (1100-60) = 1040 miles from Miame.

At 1.00 p.m. distance between two cars is 1040 miles.

Since cars travel at opposite directions, relative speed per hour = addition of two speeds = 60+70 = 130 mph

Distance = 1040 miles

Relative speed =130 mph

Hence time for their meeting = 1040/130 = 8 hours

i.e. At 9 p.m. both will meet.