The average monthly pocket money of 24 girls in a class is ₹275, whereas for 16 boys of the class it is ₹325. What is the average monthly pocket money of me whole class?

Given, 

Average monthly pocket money of 24 girls = ₹275 

we know, 

Average = $$\frac{sum\ of\ observation}{number\ of\ observation}$$

Sum of monthly income of 24 girls = $$275\times\ 24=₹6600$$

Similarly, 

Sum of monthly income of 16 boys = $$325\times\ 16=₹5200$$

Average pocket money of whole class = $$\frac{total\ pocket\ money\ of\ class\ }{total\ number\ of\ students}=\frac{\left(5200+6600\right)}{24+16}$$

i.e; $$\frac{11800}{40}=₹295$$

Hence, Option D is correct