Benjamin went shopping with 15 more ten-dollar notes than two-dollar
notes.
Let x = the number of two-dollar notes he had at first.
Let y = the number of ten-dollar notes he had at first.
...15 more ten-dollar notes than two-dollar notes...
So y = x+15
He paid $270 for a jacket with some ten-dollar notes.
After buying the jacket he had y-27 ten-dollar notes.
In the end, the number of ten-dollar notes he had left was 1/3 of the number
of two-dollar notes he had left.
So in the end he had x two-dollar notes because he didn't spend any.
y-27 = (1/3)x
x+15-27 = (1/3)x
x-12 = (1/3)x
3x-36 = x
2x = 36
x = 18
y = x+15 = 18+15 = 33
How much money did he have at first?
He had 18 two-dollar notes and 33 ten-dollar notes at first.
Edwin