Rakshanth is twice as good as tradesman as Verma and together they finish a piece of work in 19 days. In how many dayswill Verma alone finish the work?
The mean of marks secured by 45 students in division A of class X is 56, 40 students of division B is 52 and that of 40 students of division C is 50. Find the mean of marks of the students of three divisions of Class X.