There are 16 boys out of 40 students in a class. The mean marks scored by boys is 33 and those by girls is 35. Find the mean marks scored by all the students in the class.

There are 40 students in a class, out of them 15 are boys. The mean of marks obtained by boys is 33 and that for girls is 35. Find out the mean of all students in the class.

Answer the following : The mean height of 200 students is 65 inches. The mean heights of boys and girls are 70 inches and 62 inches respectively and the S.D. are 8 and 10 respectively. Find the number of boys and the combined S.D.

The mean weight of 25 students of a class is 48 kg. If the mean weight of first 13 students is 50 kg and the last 13 students is 46 kg. Find the weight of the 13th students?

Find the class mark of the class 40 - 45.

Find the class- mark of the class 35-40.