20% of the passengers on bus D got down at Yarivali bus stop and 2 passengers boarded the bus from the same bus stop. The conductor started charging from Yarivali bus stop. The number of adults and children on the bus were in the ratio 2 : 1. If the total collection of bus fare was Rs. 800, what was the bus fare for each child? Consider, there were no other stoppages till the final stop, the bus ticket was free till Yarivali bus stop and children’s ticket price was half of that of adult.