The total population of villages A and B together is

Solution

If 70% of the population of village C are working professionals which is equal to 35000.

70% of the population of village C = 35000

population of village C = 50000

The ratio between the population of village A and C is 9:10 respectively. 

population of village A = (50000/10)x9 = 45000

The total population of villages A and B together is 75000.

population of village B = 75000-45000 = 30000

‘y’% and (y+15)% of the population of village A and B are working professionals. The total non working professionals population of village B and A together is 25500.

45000 of y% + 30000 of (y+15)% = 75000-25500

450 x y + 300 x (y+15) = 49500

3 x y + 2 x (y+15) = 330

3y+2y+30 = 330

3y+2y = 330-30

5y = 300

Value of ‘y’ = 60