Here's the question you clicked on:
kaiteDID
At 10:00 a.m. two planes leave an airport. If the northbound plane flies at 280 mph and the southbound at 320 mph, at what time will they be 1,000 miles apart? { a.m.}
Distance = speed × time.
There are two distances and two speeds, but the two distances add up to 1000mi. and the time for both is the same.
320×time + 280×time = 1000.
You have to find the time.
"320+280=1000" would be 'speed + speed = distance' which doesn't make sense.
so speed + speed = distance means that it equals 600?
Speed + speed = distance is nonsensical and cannot be used. There are two distances that add up to 1000, so you need distance1 + distance2 = total distance. distance1=speed1×time, distance2=speed2×time. The only unknown here is the amount of time.
It does reduce to an equation that looks like a single speed of 600mph, and a single time of ? for a single total distance of 1000mi.
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Go back through everything I wrote a little at a time and think about it. I'm sure you'll figure it out.
is the time 4:00 a.m.?