I know the correct answer but I need you to answer my questions first
Answer:
D. Expression for Nick's distance from starting point= 6+(-4)+2
Step-by-step explanation:
Finding expression for each scenario:
A.
Number of boxes processed on on Monday =6 boxes
Number of boxes processed on on Tuesday =4 boxes
Number of boxes processed on on Wednesday =2 boxes
Expression for total boxes processed on these 3 days = 
B.
Temperature of Suma's city at noon = 6°C
Temperature of Suma's city at 8pm = 4°C
Temperature of Suma's city at noon next day = 2°F
Total temperature change = cannot be determined as all measurements are not in same units.
C
Money put on Monday = $6
Money put in Wednesday =$4
Money withdrew on Saturday = $2
Expression for balance of Re'onna's piggy bank = 
D
Distance ran north =6 miles
Distance ran south(back) = 4 miles
Distance ran north again = 2 miles
Expression for Nick's distance from starting point= 6+(-4)+2
Answer:

Step-by-step explanation:

To get
you needed to divide the numerator and denominator by 3.
Answer:
10 hours
Step-by-step explanation:
(150/x) + 1.5 + (450/(x+15)) = 600/x
Multiply through by x(x + 15):
150(x + 15) + 1.5x(x + 15) + 450x = 600(x + 15)
150x + 2250 + 1.5x^2 + 22.5x + 450x = 600x + 9000
150x + 2250 + 1.5x^2 + 22.5x + 450x - 600x - 9000 = 0
1.5x^2 + 22.5x - 6750 = 0
x = (-22.5 +/- sqrt(22.5^2 - 4(1.5)(-6750))) / (2*1.5)
x = (-22.5 +/- sqrt(506.25 + 40500)) / 3
x = (-22.5 +/- sqrt(41006.25)) / 3
x = (-22.5 +/- 202.5) / 3
x = 180/3 or -225/3
x = 60 or -75
But a negative number doesn't make sense, so therefore x = 60, so the journey took 600/60 = 10 hours.