A and B are real non-zero 3 × 3 matrices and satisfy the equation (AB)^T + B^(-1) A = 0. Prove that if B is orthogonal then A is antisymmetric.
A worker requires 8 tanks of crude oil and petrol to get a work done. He gains 5000
Ghana cedis per tank of crude oil used and 3000 Ghana cedis per petrol used for any
work done. To finish the work, he further requires 10 tanks by combining 2 tanks of
crude oil and a tank of petrol. What is the maximum profit he can make?