+12 Sherlock Homer subcontracts with nine-year-old Frances, a Baker
Street Irregular, to manufacture 50 doyles of fairnger dust. (It de-
tects fairy fingerprints). Fairnger dust is a mixture of 10% tulip
petals, 30% tea, and 60% cardboard. If tulip petals cost $4 per
doyle, tea costs $2 per doyle, and cardboard costs $1.50 per doyle,
how many dollars will it cost Frances to make enough fairnger dust?
