Answer: 95
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x = number of pounds of type A coffee
y = number of pounds of type B coffee
Keisha made 151 pounds of the blend, so x+y = 151 which solves to y = -x+151
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The second equation is 5.65*x + 4.55*y = 791.55
since 5.65*x represents the total cost of just type A alone and 4.55*y represents all of type B only. The two subtotals combine to a grand total of 5.65*x + 4.55*y which is set equal to the final cost 791.55
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5.65*x + 4.55*y = 791.55
5.65*x + 4.55*(y) = 791.55
5.65*x + 4.55*(-x+151) = 791.55 <--- replace y with -x+151
5.65*x - 4.55x + 687.05 = 791.55
1.10x + 687.05 = 791.55
1.10x+687.05-687.05=791.55-687.05 <- subtract 687.05 from both sides
1.10x = 104.5
1.10x/1.10 = 104.5/1.10 <--- divide both sides by 1.10
x = 95
