Write an equation of the line that passes through the points (0,7),(6,10)

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?

Just tell me how to set up the equation.

Which shows a reasonable estimation for 124% of 42 using the distributive property?