You Just want to get Fahrenheit alone on one side of the equal sign. Your teacher forgot to use parenthesis. The correct equation for Celsius to Fahrenheit is:
Which will give you a completely different answer....
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We will solve it using what is given:
C = (5/9)F - 32
C + 32 = (5/9)F
9(C + 32) = 5F
(9/5)(C + 32) = F
** If they mark you wrong, and try to say the answer is F = (9/5)C + 32 then they shouldn't be teaching math, and you should point out the fact there are no parenthesis around the F - 32 in the given formula.
You start with $45, and afterwards end up with $12, so subtract 12 from 45 and you end up with 33. Then divide 33 by 6, since she bought 6 snacks, and you get $5.50.