Each 4 by 4 square equals 16 square inches because 4 x 4 = <<4*4=16>>16
Three squares equals 48 square inches because 3 x 16 = <<48=48>>48
Each rectangle uses 12 square inches because 2 x 6 = <<2*6=12>>12
Both rectangles will use 24 square inches because 2 x 12 = <<2*12=24>>24
He has 1/2 of the ink left because 24 / 48 = 1/2
He has 50% of the ink left because 1/2 x 100 = <<1/2*100=50>>50
#### 50