Civil Service Exam Reviewer · Ratio and Proportion · hard
The ratio of the number of pupils to teachers in a school is 90 : 1. If there are 64 teachers, how many pupils must be added so that the ratio becomes 100 : 1?
- 6400
- 5760
- 640
- 10
Answer
C. 640
Solution
Current pupils = 90 × 64 = 5760. Needed = 100 × 64 = 6400. Add 640.
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