Multiple choice

A mixture contains 80% acid and remaining water. What quantity of mixture has been taken out and replaced by water so that the ratio of acid to the water becomes 4 : 3 in new mixture? एक मिश्रण में 80% अम्ल है और शेष पानी है। इसमें से कितना मिश्रण निकाल कर पानी मिला दिया जाये कि नए मिश्रण में अम्ल और पानी का अनुपात 4: 3 हो जाये।

  1. 1/3

  2. 3/7

  3. 2/3

  4. 2/7
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Initial mixture has 80% acid, meaning acid:water = 4:1. After removing fraction x of mixture and adding x water, acid becomes 80(1-x) and water becomes 20(1-x)+100x. For the new ratio 4:3: 80(1-x)/(20(1-x)+100x) = 4/3, which gives x = 2/7. Option D is correct.

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