Give the step-by-step reasoning process and then the final answer. A pen and pencil have a total cost of $6. If the pen costs twice as much as the pencil, what is the cost of the pen?
Let x be the cost of the pencil. If the pen costs 2 times the cost of the pencil, then it costs 2x. Adding the cost of the pen and pencil we get 2x + x = 3x. Since the total cost is $6 then 3x = $6 therefore x = $6 / 3 = $2. One pen is equal to 2 * x which is 2 * $2 = $4.
The final answer: 4.