Multiple choice

If the incomes of N and S are in the ratio of 3: 4 and their expenditures in the ratio of 4: 5. Find the ratio of their savings, given that S saves one third of her income. यदि N और S की आय में अनुपात 3: 4 है और उनके व्यय में अनुपात 4: 5 है। उनकी बचत में अनुपात ज्ञात कीजिये, यह ज्ञात है कि S अपनी आय का एक - तिहाई बचत करती है।

  1. 3: 20

  2. 17: 20

  3. 13: 20

  4. 13: 17

Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Let incomes be 3x (N) and 4x (S). Let expenditures be 4y (N) and 5y (S). Given S saves 1/3 of income: 4x/3 = 4x - 5y, so 5y = 8x/3 and y = 8x/15. N's savings = 3x - 4(8x/15) = 13x/15. S's savings = 4x - 5(8x/15) = 4x/3 = 20x/15. Ratio = 13:20. Key insight: use S's savings info to find the expenditure-to-income relationship.