That is an awful lot of Q's for one post !
1. Circumference of wheel = pi * d (inches) distance travelled for each wheel is pi * d * rpm (inches per min)
26 inch wheel pi * 26 x 200 = ~~16336.3 inches per minute
YOU do the 20 inch wheel
2.This is a conversion from in/min to mile/hr
26 inch wheel 16336.3
in / min x 1 ft / 12 in x 1 mile / 5280 ft x 60 min / hr = 15.5 m/hr
YOU do the 20 inch one
5 is an easy one 200 r /
min x 1 min / 60 sec = r/sec You can write the sentence .
3 pi 20 (x) = pi 26 (200) solve for x the number of RPM the 20 inch tire will need to keep up with the 26 inch tire
NOTE: SEE what the question asks when you get this answer ! DO THE WORK !