Question

http://prntscr.com/3i9b00

help giving out medals

Answer 1

To be able to multiply to matrices, you must have:
The number of columns of the first matrix equal to the number of rows of the second matrix.
Do you have that here?

Answer 2

In general, an "x by k" matrix multiplied by a "k by y" matrix will give an "x by y" matrix.
Notice, k of the first matrix is equal to k of the second matrix.