Since Jin donated his money to charity and he donated $864, that is our total.
We don't know the first amount, so we can call it x.
We don't know the second amount either, but we do know it was 5 times the first, so 5*x = 5x.
We first need to find how much Jin earned for the first song. We need to find x.
x + 5x = 864, then combine like terms
6x = 864, then divide both sides by 6
6x/6 = 864/4
x = 144
The fist song made $144. But the second made 5 times that. So we just multiply 144 by 5. 144*5=720.
The final answer is $720.