Andy C. answered 08/08/18
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Math/Physics Tutor
x is the # of good hammers
y is the # of better hammers
z is the # of Best Hammers
X+y+z = 100 <--- there are 100 altogether
4x+6y+7z = 520 <---- the total cost to produce them is 520 at the given cost for each
6x+9y+12z = 810 <--- the total revenue is 810
Equation 2 - 4 * equation 1: 2y + 3z = 120
equation 3 - 6* equation 1 : 3y + 6z = 210
Solves by eliminations: -3 times first equation and 2 times second equation
-6y + -9z = -360
6y + 12z = 420
3z = 60
z = 20 ----> 6y + 12(20) = 420
6y + 240 = 420
6y = 180
y = 30
So then x = 50