Answer:
4 pounds of mud
Step-by-step explanation:
Let the mud be added as [tex]x[/tex] pounds.
Given:
Cost of 1 pound of mud = $ 1.50
∴ Cost of [tex]x[/tex] pounds of mud = [tex]1.5x[/tex]
Cost of 1 pound of pitch black = $ 2
∴ Cost of 6 pounds of pitch black = [tex]2\times 6=\$ 12[/tex]
Amount of Texas T made = [tex]x+6[/tex] pounds.
Cost of 1 pound of Texas T = $ 1.80
∴ Cost of [tex]x+6[/tex] pounds of Texas T = [tex]1.80(x+6)[/tex]
Now, cost of Texas T will be equal to the sum of cost of mud and pitch black. This gives,
[tex]1.80(x+6)=1.5x+12\\1.8x+10.8=1.5x+12\\1.8x-1.5x=12-10.8\\0.3x=1.2\\x=\frac{1.2}{0.3}=4[/tex]
Therefore, he used 4 pounds of mud coffee.