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Lisa can drive 81 miles in the same amount of time it takes her to ride her bike 18 miles. if she drives at a speed that is 28 miles per hour faster than she rides her bike, how fast is she riding her bike?

Respuesta :

The speed of her bike in miles per hour is 8 miles per hour.

How to find the speed of her bike?

let

x = time she can ride 81 miles on car and 18 miles on bike

Therefore,

let the speed of the car = y + 28

speed of the bike = y

speed = distance / time

Therefore,

y + 28 = 81 / x

y = 18 / x

18 / x + 28 = 81 / x

28 = 81 / x  - 18 / x

28 = 81 - 18 / x

28 = 63 / x

28x = 63

x = 63 / 28

x = 2.25

Therefore,

y = 18 / 2.25

y = 8 miles per hour

learn more on speed here: https://brainly.com/question/9822736

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