A toy manufacturer is introducing two new dolls, My First Baby and My Real Baby. IN one hour, the company can produce 8 First Babies or 20 Real Babies. Because of demand, the company produces at least twice as many First Babies as Real Babies. The company spends no more than 48 hours per week making these two dolls. The profit on each First Baby is $3.00, and the profit on each Real Baby is $7.50. Find the number and type of dolls that should be produced to maximize profit.

I used F for fthe number of First Babies and R for the number of Real Babies. All I am sure of is that F is greater than or equal to zero, R is greater than or equal to zero and that F is greater than or equal to 2R. I am unsure of the other equations needed to be graphed, since I keep getting the wrong answers. The correct answer is 320 First Babies and 160 Real Babies. How do you get that as a maximum value?