The average marks obtained by a group of 10 students were 20. One student left the group as a result of which the average of the remaining students rose to 21. But another student joined, as a result of which the average marks of the group dropped a bit and became 20.6. What were the average marks obtained by the student who left and the one who joined?
97% of the total debt of all state power distribution companies has been covered till June 2017 under the ‘UDAY’ scheme. What does ‘D’ standfor in ‘UDAY’?