Answer:
 Matrix PQ would have the dimensions 3 X 5
Step-by-step explanation:
In order for a matrix product to be possible, the column dimension of the left factor must match the row dimension of the right factor. The resulting product will have the number of rows of the left factor and the number of columns of the right factor.
The product of a 3×4 matrix and a 4×5 matrix will have dimensions 3×5.