9514 1404 393
Answer:
367 miles per hour
Step-by-step explanation:
The speed of the faster train is half the total plus half the difference:
s1 = (723.1 +10.9)/2 = 367 . . . . miles per hour
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<em>Check</em>
The slower train is 367-10.9 = 356.1, and the total is 723.1 mph, as required.
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If you want an equation, you can let x represent the faster speed. Then the total is ...
x + (x -10.9) = 723.1
2x = 723.1 +10.9
x = (723.1 +10.9)/2 = 367
