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 = <<2*1.5=3>>3
A gallon of milk sells for the same amount as milk or butter because 3 = <<3=3>>3
She gets 48 gallons of milk because 4 x 12 = <<4*12=48>>48
She earns $144 selling the milk because 48 x $3 = <<48*3=144>>144
#### 144