Question

The monthly pocket money of Ravi and Sanjeev are in the ratio 5 : 7. Their expenditures are in the ratio 3 : 5. If each saves Rs. 80 every month, find their monthly pocket money.

Answer 1

Let the monthly pocket money of Ravi and Sanjeev be 5x and 7x respectively.

Also, let their expenditure be 3y and 5y respectively.

So, 5x – 3y = 80     ...(i)

And 7x – 5y = 80   ...(ii)

Multiplying (i) by 7 and (ii) by 5 and subtracting, we get

35x – 21y = 560
35x – 25y = 400
–      +      –        
          4y  = 160

⇒ y = 40

From (i),

5x = 80 + 3 × 40 = 200

⇒ x = 40

So, monthly pocket money of Ravi

= ₹ 5 × 40

= ₹ 200

And monthly pocket money of Sanjeev

= ₹ 7 × 40

= ₹ 280