The question is essentially asking who's equation works better (Part A) and to explain why (Part B).
Marcella is suggesting the equation 6r + 12 = 683.88
Julia is suggesting the equation 6(r + 12) = 683.88
Six people are on the trip.
It is $12 PER person to rent a floatation device.
The total cost of the trip was $683.88.
Hope I've helped!
X = y + 12. You then substitute or plug in that from the first equation into the second equation. You get (y+12)+y=18, then you simplify to get your y value. In this case y = 3. The you can plug your y value into either equation. (x+3=18) or (x-3=12) or (x=3+12) either way you get x=15 and y=3.
Let x = number of adult tickets, and y = number of children tickets. One equation must deal with the number of tickets, and the other equation must deal with the revenue from the tickets.
Then x + y = 300 is the number of tickets
12x + 8y = 3280 is the revenue from the tickets.
Using the substitution method:
x + y = 300 ⇒ y = 300 - x ⇒ Equation (3)
12x + 8y = 3280 ⇒ 12x + 8(300-x) = 3280 ⇒ x = 220
y = 300 - x ⇒ y = 300-220 ⇒ 80
Therefore 220 adult tickets and 80 children's tickets were sold.