C = 2 r π
n - number of rotations of the front wheel
n *2 r π = 6000
( n - 100 ) 2 ( r + 3 ) π = 6000
n r π = ( n - 100 ) ( r +3 ) π
n r π = n r π + 3 n π - 100 r π - 300 π / : π
3 n = 100 r + 300
2 (100 r + 300 )/3 * r π = 6000
r π ( 100 r + 300 ) = 9000
100 r² π + 300 r π - 9000 = 0 /: 100
π r² + 3 π r - 90 = 0
r = - 3π +/- √(9π² + 360π) / 2 π ≈ 4 ft
The rear wheel:
r + 3 = 7 ft ( unusual bicycle )
C = 2 r π = 2 * 7 π = 14 π ft
