E + V + R = 138
E = 3V
R = 2E - 2.......R = 2(3V) - 2....R = 6V - 2
3V + V + 6V - 2 = 138
10V - 2 = 138
10V = 138 + 2
10V = 140
V = 140/10
V = 14 <=== Vada sold 14 magazines
E = 3V
E = 3(14)
E = 42 <=== Emma sold 42 magazines
R = 6V - 2
R = 6(14) - 2
R = 84 - 2
R = 82 <=== Robbie sold 82 magazines