Bowen bought 2/5 * 40 pens = <<2/5*40=16>>16 more pencils than pens.
The total number of pencils that he bought is 40 pencils + 16 pencils = <<40+16=56>>56 pencils
If each pencil costs twenty-five cents, the total amount of money he spent on pencils is 56 pencils * $0.25/pencil = $<<56*0.25=14>>14
On pens, Bowen spent $0.15/pen * 40 pens = $<<0.15*40=6>>6
The total amount of money Bowen spent is $14 + $6 = $<<14+6=20>>20
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