Answer:
Carl has to sell at least [tex]8[/tex] cookies.
[tex]c\geq 7.5[/tex]
Step-by-step explanation:
Carl gets [tex]\$1.50[/tex] by selling 1 chocolate bar.
Earning from chocolate bars:
[tex]Total\ chocolate\ bar=20\\\\Earning\ from\ one\ chocolate\ bar=\$1.50\\\\Total\ earning\ from\ chocolate\ bar=Total\ chocolate\ bar\times cost\ of\ 1\ chocolate\ bar=20\times 1.5=\$30[/tex]
Earning From cookies:
[tex]Let\ total\ number\ of\ cookies=c\\\\Cost\ of\ 1\ cookie=\$2\\\\Earning\ from\ cookies=2\times c=2c[/tex]
[tex]Total\ earning=Earning\ from\ cookies+Earning\ from\ cookies+Earning\ from\ chocolate\ bars\\\\Total\ earning=30+2c[/tex]
Carl wants to raise at least [tex]\$55[/tex]
[tex]Total\ earning\geq 55\\\\2c+30\geq 55\\\\2c\geq 55-30\\\\2c\geq 15\\\\c\geq7.5[/tex]