20. The cost of 4 shirts, 4 pairs of dress pants, and 2 ties is $560. The cost of 9 shirts, 9 pairs of
dress pants, and 6 ties is $1,290. What is the
total cost of 1 shirt, 1 pair of dress pants, and
25
1 tie?
(A) $150
(B) $230
(C) $175
(D) $195

The slope of the line that is perpendicular to the line whose equation is 2x + y = 4 is 1/2; solution: the equation 2x + y = 4; it can be written as y =4-2x; y = -2x+4; this equation is in the form of y = mx + c; where m is the slope of [ the line. thus m = -2; the slope of the line perpendicular to the above line is m*m1 = -1; -2*m1 = -1; m1 = 1/2; ] 
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