141.You are given the net-work of air routes between the airports of three countries X, Y and Z. Find the net-work matrices connecting the countries: (i) X to Y (ii) Y to Z
147.A matrix X has a + b rows and a + 2 columns while the matrix Y has b + 1 rows and a + 3 columns. Both matrices XY and YX exist. Find a and b. Can you say that XY and YX are of the same type. Are they equal ?