Mathematics - Statistics Question with Solution | TestHub

An online exam is attempted by$50$candidates out of which$20$are boys. The average marks obtained by boys is$12$with a variance$2.$The variance of marks obtained by$30$girls is also$2.$The average marks of all$50$candidates is$15.$If$\mu$is the average marks of girls and${\sigma }^2$is the variance of marks of$50$candidates, then$\mu +{\sigma }^2$is equal to