Multiple choice

140 litres of an acid contains 90% of acid and rest water.The amount of water added to make the water 12.5% of the resulting mixture is

  1. 5 litres

  2. 4 litres

  3. 3 litres

  4. none
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Initial acid = 0.9 * 140 = 126, water = 14. We want water to be 12.5% of the new mixture. Let x be water added. 14 + x = 0.125 * (140 + x). 14 + x = 17.5 + 0.125x. 0.875x = 3.5. x = 3.5 / 0.875 = 4.

AI explanation

The initial mixture contains 10 percent water, meaning 140 liters contains 14 liters of water and 126 liters of acid. When water is added, the acid becomes 87.5 percent of the new total, so the new total volume is 126 divided by 0.875, which equals 144 liters. The amount of water added is 144 minus 140, resulting in 4 liters.

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