Word Problem

[GYPSYPAM]

The diameter of each wheel of a bicycle is 12 inches and are turning at a rate of 215 revolutions per minute . How fast is the bicyle traveling in miles per hour?.

So i know that is 2 pie times 6 therefore circumference is 12 pie inches

the i divide 12pie/6 = 6pie/3 and it equals to 6.28 feet per revolution.....but then i dont know what to do.....HELP!!!


thankyou

 

[mmm4444bot]

… circumference is 12 [pi] inches

[then I] divide 12 [pi]/6 = … 6.28 feet

I don't understand why you divided the circumference of the wheel into six pieces. Are you thinking that this converts units from inches to feet?

The circumference is 12 Pi inches.

To convert inches to feet we divide by 12.

The circumference is Pi feet.

In other words, every revolution of the wheels moves the bicycle forward Pi feet.

How many times does this happen in one minute?

Finish by converting feet/minute into miles/hour.

 

[Loren]

The diameter of each wheel of a bicycle is 12 inches and are turning at a rate of 215 revolutions per minute . How fast is the bicyle traveling in miles per hour?.

So i know that is 2 pie times 6 therefore circumference is 12 pie inches

the i divide 12pie/6 = 6pie/3 and it equals to 6.28 feet per revolution.....but then i dont know what to do.....HELP!!!


thankyou

First off, it's "pi", not "pie". If the circumference is 12 pi inches, in one revolution the bike travels 12 pi inches. That's one pi feet (approx 3.1416 feet) per one revolution. So in 215 revolutions it travels how many feet? And that is in one minute. Can you go from there? You will have to convert feet per minute to miles per hour.

 

[GYPSYPAM]

ok Sorry Pi..
so...
i did (215/1)x(1/5280)x(60/1)= 12900/5280 and my answer is 2.44 miles per hour is that right???

 

[mmm4444bot]

… i did (215/1)x(1/5280)x(60/1)= 12900/5280 and my answer is 2.44 miles per hour is that right? NO.

Your setup is okay, but one of your values is incorrect; you've actually found the speed for a bicycle that moves 1 foot forward for each revolution of the wheels.

I told you earlier that the bicycle moves Pi feet forward for each revolution of the wheels.

Remember? Each time the wheels complete one revolution, the bicycle moves forward a distance equal to the wheels' circumference.

Make the correction above, and you'll have the correct speed.

BTW, please start using an asterisk for a multiplication sign. Don't use x anymore.

215 * 1/5280 * 60, et cetera