She needs to apply sunscreen 8 times because 16 / 2 = <<16/2=8>>8
She will use 24 ounces of sunscreen because 3 x 8 = <<3*8=24>>24
This will take 2 bottles because 24 / 12 = <<24/12=2>>2
This will cost $7 because 2 x 3.5 = <<2*3.5=7>>7
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