300 ml of squash that is 20% concentrate is mixed with 200 ml of squash that is 45% concentrate. What percentage of the mixture is concentrate?
Answer and explanation
Correct answer: B. 30%
- Step 1: Concentrate in the first: 20% of 300 = 60 ml. Step 2. In the second: 45% of 200 = 90 ml. Step 3. Total concentrate 150 ml in 500 ml: 150 ÷ 500 = 30%. Answer: 30%. Why not the others: 32.5%: This is the mean of 20% and 45%, which ignores the different amounts. 35%: This is 45% - 10%, from a slip in the method. 25%: This is the mean of 20% and 30%, which uses a wrong value.
Practise more Word problems and rates.
Free questions with an explanation for every one, and full timed Independent School Entrance (ISEB Pre-Test and 11+ CEM style) mock tests.
More Word problems and rates questions
- A shop's takings from Monday to Friday were £420, £385, £510, £465 and £390. The shop wants the mean daily takings for the week to reach £45…
- A tank holds 280 litres. A tap fills it at 12 litres per minute, but a drain at the bottom empties it at 5 litres per minute. Both are on an…
- A machine only gives stamps worth 3p and 5p. What is the largest amount that CANNOT be made exactly using these stamps?
- Ali cycles at 12 km/h starting at 09:00. Beth leaves the same place at 10:00 on the same route at 20 km/h. At what time does Beth catch Ali?
- A room is 3.6 m long and 2.4 m wide. It is covered with square tiles of side 30 cm, with none cut. How many tiles are needed?
- A mother is three times as old as her daughter. In 12 years' time she will be twice as old as her daughter. How old will the mother be in 12…