The income of A is 40% less than that of B. If A gets 25% rise in his income and B gets 40% rise in his income, then the percentage increase (correct to two decimal places) in the combined incomes of A and B will be:

34.38

40% = \(\frac{2}{5}\) & 25% = \(\frac{1}{4}\) 

Ratio of        salary of A     :    Salary of B

                         3             :          5

Let salary of A = 30 & Salary of B = 50

New income of A = 30 +  \(\frac{1}{4}\) × 30 = 30 + 7.5 = 37.5

New income of B = 50 +  \(\frac{2}{5}\) × 50 = 50 + 20 = 70

Sum of new income of A & B = 70 + 37.5 = 107.5

Percentage increase in combined income =  \(\frac{107.5 - 80 }{80}\) × 100

= 34.375% 

= 34.38%    ( correct to two decimal places )