Question

Debbie rides her bike 6 miles in 30 minutes. At this rate, how many minutes will it take her to ride 21 miles?

Answer 1

105

Explanation:

Time is always x, the independent variable.

Distance, money, etc. is always y, the dependent variable, when dealing with time.

Start with the ratio of 6:30.

If you travel 6 miles in thirty minutes, how many do you have in one?

Simplify it like this:
`(6)/(30) :(30)/(30)`
`= (1)/(5): (1)/(1)`

You travel a fifth of a mile in 1 minute. Now you must find out how much it takes to get from
`(1)/(5)` to 21.

(Hint: 21 ÷
`(1)/(5)`)

You may use a calculator.

So it takes 105 minutes just to cover 21 miles, and this can be shown in fraction form as
`(21)/(105)`, or simpler,
`(1)/(5)`.

Please forgive me if I am wrong. I trusted my brain and calculator, yet I will take full blame.