Mario but 1 book. $12.60 each, Total = 12.6*1 = 12.6
Let the number of magazines be x, $2.25 each = 2.25x
Entire total cost = $23.85
12.60 + 2.25x = 23.85
2.25x = 23.85 - 12.60
2.25x = 11.25
x = 11.25/2.25
x = 5
Mario bought 5 magazines.
Hope this helped.