Answer:
Pens cost $2/each
Explanation:
We can produce an equation from this question, it is as follows:

P = The cost of pens
M = The cost of mechanical pencils
In the question it is stated that each mechanical pencil is 75 cents. We can plug that into the equation like this:

Now, we just solve the equation:

Therefore, each pen costs $2.
Let's check this answer by plugging everything into the equation:

I hope this helps!
If you have any questions feel free to ask!
- Kay :)