Ratio swap
How many adults would need to join this group of people to reverse this ratio?
Age
11 to 14
Challenge level
Problem
In a group of 48 people, the ratio of adults to children is 3 : 5.
How many adults need to join the group to make the ratio of adults to children 5 : 3?
This problem is taken from the UKMT Mathematical Challenges.
Student Solutions
Answer: 32
Image
5 + 3 = 8, 48 = 8$\times$6
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children : adults = 30 : 18 + ?
= 3 : 5
30 : 50, so ? = 32