If the average marks of three batches of 55, 60 and 45 students respectively is 50, 55, 60, then the average marks of all the students is:
53.33
54.68
55
None of these
Explanation:
Required average | =$ \left(\dfrac{55 \times 50 + 60 \times 55 + 45 \times 60}{55 + 60 + 45} \right) $ |
=$ \left(\dfrac{2750 + 3300 + 2700}{160} \right) $ | |
=$ \dfrac{8750}{160} $ | |
= 54.68 |