Rock and Roll CDs will be 5*4 = <<5*4=20>>20 dollars.
Pop CDs will be 10*4 = <<10*4=40>>40 dollars.
Dance CDs will be 3*4 = <<3*4=12>>12 dollars.
Country CDs will be 7*4 = <<7*4=28>>28 dollars.
In total Julia would need 20+40+12+28 = <<20+40+12+28=100>>100 dollars.
Julia is short 100-75 = <<100-75=25>>25 dollars.
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