Brooke is milking cows and then selling the milk at the market for $3 a gallon. Whatever milk doesn't sell, she turns into butter. One gallon of milk equals 2 sticks of butter. She then sells the butter for $1.5 a stick. She has 12 cows. Each cow produces 4 gallons of milk. She has 6 customers, each of whom wants 6 gallons of milk. How much money does she earn if she sells all her milk and butter?
A gallon of milk makes $3 worth of butter because 2 x 1.5 = 
<gadget id="calculator">2*1.5</gadget>
<output>3</output>
3.
A gallon of milk sells for the same amount as milk or butter because 3 = 
<gadget id="calculator">3</gadget>
<output>3</output>
3.
She gets 48 gallons of milk because 4 x 12 = 
<gadget id="calculator">4*12</gadget>
<output>48</output>
48.
She earns $144 selling the milk because 48 x $3 = 
<gadget id="calculator">48*3</gadget>
<output>144</output>
144.

<result>144</result>