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?
A bank offers 5% compound interest per half year. A customer deposits Rs 4800 each on 1st January and 1st July of a year. At the end of the year, the amount he would have gained by way of interest?