20 litres of solution contain 30% alcohol. After 10 litres of water are added, what is the alcohol concentration?
Answer and explanation
Correct answer: C. 20%
- Step 1: Alcohol = 0.30 x 20 = 6 litres, which does not change. Step 2. New volume = 30 litres, so the concentration = 6 / 30 = 20%. Answer: 20%. Why not the others: The volume rises by half, so the concentration falls to two-thirds of 30%, not to a half.
Practise more Logical Reasoning.
Free questions with an explanation for every one, and full timed Prueba Unica Nacional (Peru Teacher Appointment Test) mock tests.
More Logical Reasoning questions
- What number comes next in the series 5, 9, 13, 17, ... ?
- What number comes next in the series 2, 6, 18, 54, ... ?
- In the series 1, 1, 2, 3, 5, 8, ... each term follows a rule. Which term comes next?
- What number comes next in the series 1, 4, 9, 16, 25, ... ?
- What letter comes next in the series A, C, F, J, O, ... ?
- Rule: 'If it rains, the school yard is closed.' The yard is open today. Which conclusion is certain?