If the volumes of two right circular cones are in the ratio 1:4 and their diameters of bases in the ratio 4:5, then their heights will be in the ratio:
The mean of marks secured by 35 students in division A of class X is 65, 45 students of division B is 61 and that of 70 students of division C is 59. What is the mean of marks of the students of three divisions of Class X?