10. Ms Yomunde is a well-established contractor in the Zambezi region. She wants to build more catchment dams on her farm. She needs at least 1 200kg sand, at least 800kg gravel and at least 480kg cement. Build-Cheap offers packed crates of 600kg sand, 200kg gravel and 60kg cement. Make-Easy also offers packed crates with 200kg sand, 200kg gravel and 160kg cement. Build- Cheap asks N$500 for a container of materials and Make-Easy N$400. Required Calculated the total quantity of cement to be used by the farmer if the optimal option is applied. (Note: Use simultaneous equations only)