Multiple choice

In a mixture of $45$ litres, the ratio of milk and water is $4:1.$ How much water must be added to make the mixture ratio $3:2$?

  1. $18$ litres
  2. $15$ litres
  3. $21$ litres
  4. $25$ litres
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Initial mixture: 45L, ratio 4:1 (36L milk, 9L water). New ratio 3:2. Let x be water added: 36 / (9 + x) = 3 / 2. 72 = 27 + 3x, 3x = 45, x = 15.

AI explanation

The initial mixture contains 4 parts milk and 1 part water for a total of 5 parts, meaning the volume of one part is 45 liters divided by 5, or 9 liters. This gives 36 liters of milk and 9 liters of water. If x liters of water are added, the new ratio of milk to water is 36 to 9 plus x, which is set equal to 3 to 2. Solving 36 multiplied by 2 equals 3 multiplied by 9 plus x gives 72 equals 27 plus 3x, so x is 15 liters.

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