Please can someone answer these please

How do i do this? i don’t understand

If 30 lb of rice and 30 lb of potatoes cost ? $27.60? , and 20 lb of rice and 12 lb of potatoes cost ? $15.04? , how much will 10 lb of rice and 50 lb of potatoes? cost?

The vertices of a triangle are a(7.5), b(4,2), and c19. 2). what is