Answer:
B. 26 rpm
Explanation:
The sprocket has a diameter of 10 in
The back wheel has a diameter of 6.5 in
One complete revolution formula is : 2πr -------where r is radius
For the sprocket , one revolution = π * D where D=2r
π * 10 = 31.4 in
For the back wheel, one revolution = π* 6.5 = 20.42 in
The pedaling rate is : 40 rpm
Finding the ratio of revolutions between the sprocket and the back tire.
In one revolution; the sprocket covers 31.4 in while the back tire covers 20.42 in so the ratio is;
20.42/ 31.4 = 0.65
So if the speed in the sprocket is 40 rpm then that in the back tire will be;
40 * 0.65 = 26 rpm
