1/4 = 5/20
2/5 = 8/20
8/20 + 5/20 = 13/20 has been spent
Answer: Second option.
Step-by-step explanation:
Let be "e" the number of easy puzzles Tina solved and "h" the number of hard puzzles Tina solved.
Set up a system of equations:

You can use the Eliminationn Method to solve this system of equations:
- Multiply the first equation by -30.
- Add the equations.
- Solve for "h".
Therefore, through this proccedure, you get:

False I think it doesn't add up to 18
For this case we have to:
Lewis carries 2 liters of water
Garret carries 1 liter of water
So, Lewis has 1 liter of water more than Garret.
By definition we have that 1 liter equals 1000 milliliters.
Thus, Lewis carries 1000 milliliters more water than Garret.
Answer:
1000 milliliters