(n5/n3a)*(n3a/n2)*(n2/n1b)=
(n denotes no. of teeth in the gear)
(9/12)*(12/10)*(10/14)=
(9/14)
(n1a/n4b)*(n4a/n3b)*(n3a/n5)=
(40/10)*(19/10)*(12/9)=
(152/15)
(152/15)*(9/14)=
6.5
This value of overall ratio nearly equal to 6.5 shows that for one rotation of the tyre in the backward direction,the tyres of the car rotate 6.5 times and hence the car moves 6.5 times the distance travelled in the backward direction.This clearly explains why the car goes a larger distance in the forward direction.