A boat running downstreams covers a distance of 30 kms in 2 hours. While coming back the boat takes 6 hours to cover the same distance. If the speed of the current is half that of the boat, what is the speed of that boat in kmph ?
In a college the number of students studying Arts, Commerce and Science are in the ratio of 3 : 5 : 8 respectively. If the number of students studying Arts, Commerce and Science is increased by 20%, 4 0% and 2 5 % respectively, what will be the new ratio of students in Arts, Commerce and Science respectively ?