Given, The ratio of incomes of two persons is 9 : 7

Let the income is 9x and 7x

Again, the ratio of their expenditures is 4 : 3

Let their incomes are 4y and 3y

Now, Saving = Income - Expenditure

=> 9x - 4y = 200  .............1

and 7x - 3y = 200  ............2

From equation 1 and 2, we get

     9x - 4y = 7x - 3y

=> 9x - 7x = 4y - 3y

=> 2x = y

Now, 2x = y = 200

=> 2x = 200

=> x = 200/2

=> x = 100

and y = 200

Now the income = 9x and 7x

                      = 9 * 100 and 7 * 100

                      = Rs 900 and Rs 700