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| Math Central | Quandaries & Queries |
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Question from Corey: Walking up a broken escalator (escalator not working) takes 75 seconds. Riding up the same escalator (not walking) when it is working takes 45 seconds. How long would it take a person to walk up the escalator when it is working ? |
Corey,
- When you are walking up you go a distance of 1 floor in 75 seconds so your speed is 1/75 (one floor every 75 seconds).
- When you are riding up, your speed is 1/45.
- When you are walking up an operating escalator, your speed is combined: 1/45 + 1/75.
- Remember that time = distance/speed. The distance is still 1 floor. So t = 1 / (1/45 + 1/75). Calculate t.
Cheers,
Stephen La Rocque.
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