Multiple choice

A scientist mixes 10% water in his solution but he is not content with it so he again mixes 10% more water in the previous mixture. What is the profit percentage of the scientist if he sells it at cost price?

  1. 15%

  2. 21%

  3. 18%

  4. 16%

  5. None of these
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Successive increase of 10% and 10% is 10 + 10 + (10*10)/100 = 21%. Selling at cost price means the profit is the percentage increase in volume.

AI explanation

Let the initial quantity of the pure solution be 100 units, meaning the first addition of 10% water increases the total volume to 110 units. Adding 10% water again to this new mixture increases the volume by 11 units, making the final total volume 121 units. Since the scientist only paid for 100 units but sells 121 units at the same cost price per unit, his profit percentage is calculated as (121 minus 100) divided by 100 times 100. The profit percentage of the scientist is 21%.

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