Find the total surface area of a triangular prims

Amerchant has coffee worth $60 a pound that she wishes to mix with 50 pounds of coffee worth $90 a pound to get a mixture that she will sell for $70 a pound. how many pounds of the & 60 coffee should be used?

Will used 20 colored tiles to make a design in art class. 5/20 of his tiles were red. what is an equivalent fraction for the red tiles?

You earn a 12% commission for every car you sell. how much is your commission if you sell a $23,000 car?