It will most likely to be 15 nights.
1/3 is what you are dealing with and 3/3=1 so I am thinking...
if she is doing 1/3 each night 3/3 is 3 nights which equals one hour
To get the second hour along with the rest of the hours you just have to count until you get five hours or you can just multiply 3x5 which also equals 15
I hope this helped
