Cement Mix A 20-pound bag of Economy brand cement mix contains 25% cement and 75% sand. How much pure cement must be added to produce a cement mix that is 40% cement?

GAUSS ELEMINATION METHOD Augmented Matrix Elementary Row Operations Row Echelon Form Augmented Matrix – A matrix in which the values on the other side of the equal sign is included in the matrix. It is written in the left most column with a dotted line separating it from the other values of the matrix. Row Echelon Form – the form of matrix in which the first entry in each row is Zero. The non – zero leading entry of the other rows are indented to the left of the zero in the lower row and the ‘all zero row’ is at the bottom of the matrix. Example of the Row Echelon form. To find the vector form of the matrix, find the Row Echelon Form and then assign each row a variable. Then write the entire row with the assigned variabl