Eight persons were killed and 20 injured on Saturday when a truck collided with a dumper in Ujjain, Madhya Pradesh, police said.The victims were travelling to Nalkheda from Alirajpur on a truck to buy cattle from a cowshed there. When the truck reached Pulia village, a dumper collided with it, killing eight persons on board and injured 20 others, Ghatiya police station In-charge, J.R. Chauhan told IANS.Of the 20 injured, five were in critical condition and shifted to Indore for treatment.