ANSWER
$12.56
EXPLANATION
Orange costs $3.42 for 9 pounds.
We want to know how much it would cost to get 12 pounds of oranges.
To do this, we will simply compare and make our unkown x:
$3.42 = 9 pounds
x = 12 pounds
Now, we cross multiply:
=> x * 9 = 3.42 * 12
At this rate, 12 pounds will cost $4.56.