JEE Main 2023 Mathematics question
Let the mean and standard deviation of marks of class A of 100 students be respectively 40 and (>0), and the mean and standard deviation of marks of class B of n students be respectively 55 and 30 – . If the mean and variance of the marks of the combined class of 100 + n students are respectively 50 and 350, then the sum of variances of classes A and B is :
Answer: (D)