David Gwyn J. answered 11/03/20
Highly Experienced Tutor (Oxbridge graduate and former tech CEO)
Iced tea costs $2.00 per gallon and lemonade costs $2.50 per gallon
if x represents the number of gallons of iced tea
2x
and y represents the number of gallons of lemonade
2.5y
He can spend at most $24.00
≤ 24
so we need 2x + 2.5y ≤ 24 and only A fits this
(As only A fits, you don't need to figure out gallons. But 5 is correct because 24 - 12.50 = 11.50 which is 5 gallons of iced tea and $1.50 left.)
A truck rental company charges $90 plus $20 per hour
f(h) = 90 + 20h
Only answer A fits.
Similarly, as only one answer has the equation, you don't have to work out the rest of the question.
But f(h) is cost function, f(5) = 90 + 5(20) = $190 and is cost for renting truck for 5 hours.