Ethan bought a bag of marbles. After giving 1/5 of his marbles to Jacob and 105 marbles to Adam, he had 1/3 of the marbles left. How many marbles did Ethan buy?
Ethans marbles
; x-1/5x-105=1/3x
:x-3/15x-105=5/15x
:12/15x-105=5/15x
:7/15x=105
:1/15x=15
:x = 225
