The ratio of the monthly incomes of A and B is 3:4. The ratio of the monthly expenditures of A and B is 4:5. Which of the following represents a possible value of the ratio of their savings?a.13:20b.9:10c.4:5d.3:4

To solve this problem, we need to understand that savings is income minus expenditure.

Let's denote the monthly income of A as 3x and of B as 4x. Similarly, let's denote the monthly expenditure of A as 4y and of B as 5y.

The savings of A would then be 3x - 4y and the savings of B would be 4x - 5y.

We are asked to find the ratio of their savings, which is (3x - 4y) : (4x - 5y).

We don't have specific values for x and y, so we can't calculate a specific ratio. However, we can see that the ratio of their savings depends on the values of x and y.

If we look at the options given:

a. 13:20 - This could be a possible ratio if x and y are chosen such that (3x - 4y) / (4x - 5y) equals 13/20.

b. 9:10 - This could also be a possible ratio if x and y are chosen such that (3x - 4y) / (4x - 5y) equals 9/10.

c. 4:5 - This is not a possible ratio because it's the same as their expenditure ratio. Since savings is income minus expenditure, their savings ratio cannot be the same as their expenditure ratio.

d. 3:4 - This is not a possible ratio because it's the same as their income ratio. Since savings is income minus expenditure, their savings ratio cannot be the same as their income ratio.

So, the possible values for the ratio of their savings could be 13:20 or 9:10.