If I were to increase the length of my stride by one inch it

If I were to increase the length of my stride by one inch, it would take me 60 fewer strides to cover a mile. What was the length of my original stride?

Solution

Let lenght of original stride be x inches.
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Original number of stides required: (5280*12)/x
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New number of strided required: (5280*12)/(x+1)
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Equation:
old number - New number = 60
(5280*12)/x - (5280*12)/(x+1) = 60
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Divide both sides by 12 to get:
5280/x - 5280/(x+1) = 5
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Divide thru by 5280 to get:
1/x - 1/(x+1) = 5/5280
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(x+1-x)/(x(x+1)) = 1/1056
(1/(x(x+1)) = 1/1056
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x^2 + x- 1056 = 0
Factor: (x-32)(x+33) = 0
Positive solution:
x = 32 inches (his original stride length)