Math
posted by Anonymous .
A manager bought 12 pounds of peanuts for $30. He wants to mix $5 per pound cashews with the peanuts to get a batch of mixed nuts that is worth $4 per pound. How many pounds of cashews are made?

look at the value of the nuts separately and together:
30 + 5(x) = 4(12+x)
30 + 5x = 48 + 4x
x = 18