Answer:
a= 6
b = 7
c = 8
d = 7
e = 6
Step-by-step explanation:
Notice that the bike is 6 feet above the ground to start with, so when it starts rolling, the green dot is exactly 6 feet from the ground, which gives a=6
when the distance covered by the bike is 
, (see first red dot in the attached image), the position of the green dot is exactly 1 foot added to 6 ft= 7 feet
so b = 7
when the distance covered is 
, now the green dot would be at the top of the wheel (second red dot in the attached image) which involves adding 2 feet to the original 6 feet. That is: c = 8
when the distance covered is 
, the green dot is at the position of the third red dot in the attached image., that it exactly one foot added to 6 feet = 7 ft which gives the value of d = 7
and finally, when the distance covered is 
. the green dot has completed a full circle and is now again in its lower position (nothing - zero) added to 6 feet = 6ft, giving e = 6.
