SOLUTION: Ryan took 15 minutes to walk to school at an average speed of 70 m/min. His brother took 20 minutes to walk the same distance. Determine his brother’s average speed.

Algebra ->  Percentage-and-ratio-word-problems -> SOLUTION: Ryan took 15 minutes to walk to school at an average speed of 70 m/min. His brother took 20 minutes to walk the same distance. Determine his brother’s average speed.       Log On


   

Question 1102271: Ryan took 15 minutes to walk to school at an average speed of 70 m/min. His brother took 20 minutes to walk the same distance. Determine his brother’s average speed.
Found 3 solutions by ikleyn, josgarithmetic, greenestamps:
Answer by ikleyn(52776) About Me  (Show Source):
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1.  The distance is  15 min * 70 m/min, calculated using Ryan's data.


2.  The brother' speed is  %2815%2A70%29%2F20 =  52.5 m/min.


Answer by josgarithmetic(39616) About Me  (Show Source):
Answer by greenestamps(13198) About Me  (Show Source):
You can put this solution on YOUR website!


This is a good example of inverse variation: the faster you move, the less time it takes; the slower you move, the more time it takes.

Ryan took 15 minutes to walk to school; his brother took 20 minutes. The ratio of the times is 3:4.
Since the distance is the same for both of them, the ratio of the speeds is 4:3.

So Ryan's brother's speed is 3/4 of Ryan's speed: %283%2F4%29%2A70+=+52.5