Answer:
135 boys : 90 girls
Explanation:
The sum of ratio units is 9+6 = 15. Then each ratio unit must stand for ...
225/15 = 15 . . . campers
Multiply the ratio by 15 to find the numbers of interest.
boys : girls = 9 : 6 = 135 : 90
There were 135 boy and 90 girl campers.