What single discount is equivalent to successive discounts of 10% and 20%

Olga used 100 ounces of flour to make 225 muffins. how many ounces of flour will be used to make 300 muffins?

If f(x)=-x^2+6x-1 and g(x)=3x^2-4x-1,find(f+g)(x)

Select the number of ways in which a line and a circle can intersect