Bryan paid a total of 36.30 for pens and 3 files. If he had bought 2 pens and 6 files, he would need $48.60. What was the cost of each pen and each file?
(a) 2p+6f = 48.60
xp+3f = 36.30
(b) 2xp+6f = 72.60
subtract (a) from (b) and you have
2(x-1)p = 24.00
(x-1)p = 12.00
so a pen's cost is a divisor of 12.00
See what you can do with that.
Or maybe you just forgot to say how many pens were included in the $36.30 part.