A train travels 70 mph for x hours and then 80mph for 3$\frac3{3}{4}$ hours. If the train is coverung 405 miles of track, find the value of x. [closed]

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A train travels 70 mph for x hiurs and then 80mph for 3$\frac{3}{4}$ hours. If the train is coverung 405 miles of track, find the value of x.

I don't know how to answer this question. Thank you and help is appreciated.

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2 Answers

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$$ \text{Distance} = \text{Speed} \cdot \text{Time}$$

Since the total distance travelled must be the same on both sides, we have the equation:

$$70x + 80 \cdot 3 \frac{3}{4} = 405$$

Now solve for $x$.

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Although you have written mph, but as it is a train i'm thinking it's kmph and as the train is covering 405 miles in question you need to convert it into km by multiplying 1.609. So, we have the distance 405×1.609=651.645(approax.)(whereas the better approaximation is 651.784 but that doesn't matter). Thus the equation is (as speed×time=distance): 70x+80×15/4=651.645=> x=351.645/70.

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