The ratio of the incomes of A and B last year was 4:3, respectively. The ratios of their individual incomes of the last year and the present year are 3:4 and 5:6, respectively. If their total income for the present year is ₹8.04 lakh, then the income of B last year was:

Hi Niloy can you please expand on how we get the ratio for the second years?

How did you get the equation for second year?

Let the income of A and B previous year be 4x and 3x. Therefore, present year income A will be 16x/3 and B will be 18x/5.
Therefore, according to qn,
16x/3 + 18x/5=8.04
this gives x=0.9
therefore, income of B last year is 3x=3*0.9 lakh=2.7lakh