You know that 15% of a number n is 12. how can you use this to find 30% of n? 45% of n? explain. because 30% of n is equal to [ ] times 15% of n and 45% of n is equal to [ ] times 15% of n, you can write 30% of n=[ ] ×12= [ ] and 45% of n= [ ] ×12= [ ]