The ratio of monthly incomes of A and B is 4 : 5 and that of their monthly expenditures is 3 : 8. If the income of A is equal to the expenditure of B, then what is the ratio of savings of A and B?

The ratio of monthly incomes of A and B is 4 : 5.

Let the monthly incomes of A and B are 4p and 5p respectively.

The income of A is equal to the expenditure of B.

Monthly expenditure of B = 4p

The ratio of monthly expenditures of A and B is 3 : 8.

Monthly expenditure of A = $$\frac{3}{8}\times$$4p = $$\frac{3}{2}$$p

The ratio of savings of A and B = (4p - $$\frac{3}{2}$$p) : (5p - 4p)

= $$\frac{5}{2}$$p : p

= 5 : 2

Hence, the correct answer is Option D