Ryan's Coffee Shop makes a blend that is a mixture of coffee types A and B. In one bag of the blend, there are kilograms of type A. Four bags of the blend are a total of kilograms. How many kilograms of type B are there in one bag?

(a) Write an equation that could be used to answer the question above. First, choose the appropriate form. Then, fill in the blanks with the numbers , , and . Let represent the number of kilograms of type B in one bag.
blank (b + blank) = blank
blank (b - blank) = blank
(b) Solve the equation in part (a) to find the number of kilograms of type B in one bag.
b= blank