b2bt
Bunuel
Official Solution:
The radius of the front wheels of a cart is half that of the rear wheels. If the circumference of the front wheels is 1 meter and the cart traveled 1 kilometer, how many revolutions did the rear wheels make?
A. \(\frac{250}{\pi}\)
B. \(\frac{500}{\pi}\)
C. 250
D. 500
E. 750
The circumference of the rear wheels is twice that of the front wheels, i.e. 2 meters. Thus, the rear wheels made \(\frac{1000}{2} = 500\) revolutions.
Answer: D
I thought we have to divided the distance i.e. 1000 meters with circumference i.e. 4\({\pi}\) and hence the answer should be \(\frac{250}{{\pi}}\)
but I guess in the solution you have divided the the distance with radius. Is it so?
No. We are given that the
circumference of the front wheels is 1 meter and the radius of the front wheels is half that of the rear wheels.
Thus, the
circumference of the front wheels is \(2\pi{r}=1\) and the
circumference of the rear wheels is \(2\pi{(2r)}=2*2\pi{r}=2\).
So, we
are dividing the distance with the circumference.
Hope it's clear.