(Production Planning) A manufacturer makes three different types of chemical 
products: A, B. and C. Each product must go through two processing machines: 
X and Y. The products require the following times in machines X and Y: 
I. One ton of A requires 2 hours in machine X and 2 hours in machine Y. 
2. One ton of B requires 3 hours in machine X and 2 hours in machine Y. 
3. One ton of C requires 4 hours in machine X and 3 hours in machine Y.