An automobile has 20 inch diameter wheels. If the wheels revolved three times after the brakes were applied, the stopping distance was approximately?

Question

ash2326 · Answer

Diameter of wheels 20 inch so radius = 10 inch
Wheels revolved 3 times after the breaks  were applied , so  the distance would be  3 times the perimeter
Perimeter of circle= $2 \pi r$
so Distance covered = $3 \times 2 \times \pi \times r$
Can you solve it now???

anonymous · Answer

I got 3 *2* 3.14*10= 188.4. But thats not one of my choices on my paper?

ash2326 · Answer

What are the options???

anonymous · Answer

A. 26.2
b. 157
c. 7.85
d. 15.7

ash2326 · Answer

are the units given in options??

anonymous · Answer

yes they are all ft..

ash2326 · Answer

feet:D:D
$$3 *2* 3.14*10= 188.4\ inches$$
1 feet = 12 inches
so
$$Distance in feet= \frac{188.4}{12}$$

anonymous · Answer

okay so i got 15.45 ft.

ash2326 · Answer

You should recalculate it'd be 15.7
188.4/12=(180+8.4)/12=15+0.7= 15.7 feet

anonymous · Answer

okay i got it now.