Multiple choice

Vessels A and B contains mixture of copper and zinc.Copper content is 80% and 62.5% in vessel A and B respectively.25 kg of mixture is taken out from vessel A and poured into vessel B so that copper content becomes 100% more than that of zinc in vessel B. If new quantity of mixture in vessel B is 16% less than initial quantity of mixture in vessel A. Find initial quantity of copper in vessel A?

  1. 80 Kg

  2. 160 Kg

  3. 120 Kg

  4. 140 Kg

  5. 100 Kg

Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

Let initial quantities in A and B be a and b. A has 80% copper = 0.8a, B has 62.5% copper = 0.625b. After transferring 25 kg from A to B, B's new copper = 0.625b + 0.8*25 = 0.625b + 20. B's zinc becomes 0.375b + 5. New copper in B is 100% more than zinc means: 0.625b + 20 = 2 * (0.375b + 5). Solving: 0.625b + 20 = 0.75b + 10 gives 0.125b = 10, so b = 80. New quantity in B = b + 25 = 105, which is 16% less than a. So 105 = 0.84a, giving a = 125. Initial copper in A = 0.8 * 125 = 100 kg. Option E is correct.