Answer:
100 pens
How??
Key-
x represents profit
y represents pens needed to make 50 dollars
Okay, first. We need to find out how much profit he is making per pen. Since he is buying them at 4 and sells at 4.50. We can do the following equation and solve it to find profit.
4.50-4
4.50-4=x
.5=x
So, he makes a profit of 50 cents per pen. Now, to find how much pens we need to sell. We would do the following equation and solve.
50/0.5
50/0.5=y
100=y
Thus, I know that the true answer to this problem is 100
