Multiple choice

A can is full of paint. Out of this 5 litres are removed and thinning liquid substituted. The process is repeated. Now the ratio of paint to thinner is 49 : 15. What is the full capacity of the can? एक कैन पेन्ट से भरा हुआ है। इसमें 5 लीटर निकाल कर पतला करने वाला द्रव मिलाया गया। यह प्रक्रिया दोहरायी गयी। अब पेन्ट और पतला करने वाले द्रव का अनुपात 49 : 15 है, तो कैन की पूरी धारिता क्या है?

  1. 20 litres/ लीटर

  2. 60 litres/ लीटर

  3. 40 litres/ लीटर

  4. 50 litres/ लीटर
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Let capacity be C litres. After first operation: paint = C-5, thinner = 5. After second operation (removing 5 litres of mixture): paint remaining = (C-5) - 5(C-5)/C = (C-5)(C-5)/C. The ratio paint:total volume becomes (C-5)²/C² = 49/64 (since 49:(49+15) = 49:64). Solving (C-5)²/C² = 49/64 gives (C-5)/C = 7/8, so 8C-40 = 7C, hence C = 40.

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