In a town, 60% of residents own a bicycle and 40% own a car. If 20% of residents own neither, what percentage of residents own both a bicycle and a car?
Answer and explanation
Correct answer: A. 20%
- Step 1: By the principle of inclusion-exclusion, Total = B + C - (B and C) + Neither.
- Step 2: 100% = 60% + 40% - Both + 20%.
- Step 3: 100% = 120% - Both.
- Step 4: Both = 120% - 100% = 20%.
Answer
20%.
Why not the others: 25% computes (60 - 40) + 5; 15% is an arithmetic error; 30% forgets to include the 20% who own neither.
Practise more Algebra, Number Properties and Arithmetic Problem Solving.
Free questions with an explanation for every one, and full timed Psychometric Entrance Test (PET Israel) mock tests.
More Algebra, Number Properties and Arithmetic Problem Solving questions
- If n is a positive integer such that 72*n is a perfect cube, what is the smallest possible value of n?
- The average of five distinct positive integers is 24. If the median of these five numbers is 20, what is the maximum possible value of the l…
- Pipe A fills a reservoir in 6 hours, and Pipe B fills it in 8 hours. Pipe C drains the full reservoir in 12 hours. If all three pipes are op…
- A worker's salary was increased by 20%, and one year later reduced by 20%. How does the final salary compare to the original salary?
- What is the remainder when 3^100 is divided by 7?
- A container holds 60 liters of a mixture of wine and water in the ratio 3:1. How many liters of water must be added so that the ratio of win…