In an examination, the average marks of 60 girls is 15 and the average marks of 40 boys is 30. The average marks of the group in which the boys and girls are taken together is :
Answer & explanation
Correct answer: option 2
Sum of marks of 60 girls = 60 × 15 = 900
Sum of marks of 40 boys = 40 ×30 = 1200
Average marks of whole group = \(\frac{1200 + 900 }{100}\) = 21