Answer:
Her brothers ate 2 slices
Explanation:
Ok so first thing we know is there are 32 pieces
now let's find out how many slices the birthday girl ate
she ate 2 slices because 16x2=32 and she ate 1/16 of the birthday cake
that leaves use with 30 slices left
next we have to find out how many slice her friends ate
4 goes into 32 8 times and 3x8= 24 so her friends ate 24
30-24=6
now it says the brothers ate 1/3 of the last pieces of cake which we know is 6 slices so 1/3 oh six is 2
Her brothers ate two slices