Answer:
If half of the squares on Kerion's paper are blue, that means there are 1/2 blue squares.
Out of the blue squares, 1/3 of them will have stripes.
So the fraction of squares that will be blue with stripes is 1/2 * 1/3 = 1/6.
Another way to think about it is that for every six squares on the paper, one of them will be blue with stripes.