Question

The ratio of monthly income of A and B is 3: 4 and the ratio of their monthly savings is 7: 6, if the income of A is equal to twice the expenditure of B, then what is the ratio of expenditure of A and B?​​

Answer 1

Answer:-

Given:

Ratio of monthly income of A & B = 3 : 4.

Ratio of their monthly savings = 7 : 6

Let the incomes of A & B be 3x , 4x and let their savings be 7y , 6y.

Also,

→ Income of A = 2 * Expenditure of B

→ 3x = 2 * Expenditure of B

→ 3x/2 = Expenditure of B.

We know that,

Expenditure = Income - savings

Hence,

→ Expenditure of B = Income of B - Savings of B

→ 3x/2 = 4x - 6y

→ 3x/2 - 4x = - 6y

→ (3x - 8x)/2 = - 6y

→ (- 5x/2) * (- 1/6) = y

→ 5x/12 = y -- (1)

Similarly,

→ Expenditure of A = Income of A - Savings of A

→ Expenditure of A = 3x - 7y

Substitute y value from equation (1).

→ Expenditure of A = 3x - 7(5x/12)

→ Expenditure of A = (36x - 35x)/12

→ Expenditure of A = x/12

Now,

Ratio of their expenditures = [ x/12 ] / [ 3x/12 ]

→ Ratio of their expenditures = (x/12) * (12/3x)

→ Ratio of their expenditures = 1 : 3

Answer 2

Step-by-step explanation:

let, monthly income of A is 3x and B is 4y

and monthly savings of A is 7y and B is 6y

so, expenditure of A is (3x-7y) and B is(4x-6y)

as per the question,

• A is equal to twice the expenditure of B,

then, 3x=2*6y

3x=12y

so, expenditure of A is (3x-7y)

or(12y-7y) =5y

and B is(4x-6y)

or, (16y-6y) =10y

so, ratio of expenditure of A and B is 5y:10y=1:2