Answer:
$ 2.167
Step-by-step explanation:
Let the cost of a pencil be x and that of a pen be y.
A pen costs twice as much as a pencil.
==> cost of a pen = 2 × cost of a pencil
==> y = 2x
Their total cost is $6.50
==> x + y = $6.50
since y = 2x, substituting y for 2x
==> x + 2x = 6.50
==> 3x = 6.50
dividing both sides by 3
==> x = 2.16
As per our assumption, x is the cost of one pencil.
Therefore, the cost of a pencil is $2.167
