Explanation:

Here’s a step-by-step explanation:

- Total students in class = 45

- Percentage of girls = 40% of 45 = 18 girls

- Remaining boys = 45 - 18 = 27 boys

- Average marks of girls = 64

- Total marks for girls = 18 * 64 = 1152

- Average marks of boys = 60

- Total marks for boys = 27 * 60 = 1620

- Total marks for the class = 1152 + 1620 = 2772

- Average marks for the class = Total marks / Total students = 2772 / 45 = 61.6

The average marks of the whole class is 61.6, which matches Option 3.

Option:3, 61.6