Julia buys 4 * 3 = <<4*3=12>>12 pens

Dorothy buys 12/2 = <<12/2=6>>6 pens

The total number of pens purchased is 4 + 12 + 6 = <<4+12+6=22>>22 pens

The total cost of the pens is 22 * $1.50 = $<<22*1.5=33>>33

# Answer

33
<|im_start|>system
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<|im_start|>user
Dorothy, Julia, and Robert go to the store to buy school supplies. Dorothy buys half as many pens as Julia. Julia buys three times as many pens as Robert. Robert buys 4 pens. If one pen costs $1.50, how much money did the three friends spend in total on pens?
Please reason step by step, and put your final answer within \boxed{{}}.<|im_end|>
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user
33
Dorothy, Julia, and Robert go to the store to buy school supplies. Dorothy buys half as many pens as Julia. Julia buys three times as many pens as Robert. Robert buys 4 pens. If one pen costs $1.50, how much money did the three friends spend in total on pens?
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