X
2 1\12 X = 25\12X
25\12 X = X + 520
X*(25\12 - 12\12) = 520
13\12X = 520
13\12X = 6240\12
13X = 6240
X = 480
25\12X = 1000
X
2 1\12 X = 25\12X
25\12 X = X + 520
X*(25\12 - 12\12) = 520
13\12X = 520
13\12X = 6240\12
13X = 6240
X = 480
25\12X = 1000