Answer:
765
Step-by-step explanation:
First, find the number of sophomores
3600 * 3/8 =1350
Use the number of sophomores and multiply by 3/5 to find the amount of sophomores opposed to rock climbing
1350 * 3/5 =810
Then subtract the amount of sophomores from the total amount of students
3600 - 1350 =2250
And multiply the remaining students by 9/10 to find the amount of non-sophomores opposed to rock climbing
2250 * 9/10 =2025
Add the amount of sophomores and non-sophomores opposed to rock climbing
810 + 2025 =2835
The amount of students in favor of rock climbing would be
3600 - 2835 =765