11. A fish tank requires 8 liters of water to fill. Alejandro filled the tank with [tex]$2 \frac{11}{15}$[/tex] liters of water. Anthony poured [tex]$1 \frac{3}{5}$[/tex] liters less than Alejandro into the tank. How much water does the tank still need for it to be filled?

a) [tex][tex]$2 \frac{1}{5}$[/tex][/tex]
b) [tex]$4 \frac{2}{15}$[/tex]
c) [tex]$3 \frac{2}{15}$[/tex]
d) [tex][tex]$1 \frac{1}{5}$[/tex][/tex]



Answer :

To determine how much water is still needed to fill the fish tank after Alejandro and Anthony have poured their amounts, let's solve this step-by-step.

1. Convert Mixed Numbers to Improper Fractions:

- Alejandro's water: [tex]\( 2 \frac{11}{15} \)[/tex]
[tex]\[ 2 \frac{11}{15} = 2 + \frac{11}{15} = \frac{30}{15} + \frac{11}{15} = \frac{41}{15} \][/tex]

- Anthony poured [tex]\( 1 \frac{3}{5} \)[/tex] liters less than Alejandro:
[tex]\[ 1 \frac{3}{5} = 1 + \frac{3}{5} = \frac{5}{5} + \frac{3}{5} = \frac{8}{5} \][/tex]

2. Convert [tex]\( \frac{8}{5} \)[/tex] to a common denominator of 15:
[tex]\[ \frac{8}{5} = \frac{8 \times 3}{5 \times 3} = \frac{24}{15} \][/tex]

3. Determine Anthony's water, which is [tex]\( \frac{41}{15} - \frac{24}{15} \)[/tex]:
[tex]\[ \frac{41}{15} - \frac{24}{15} = \frac{41 - 24}{15} = \frac{17}{15} \][/tex]

4. Calculate the total water poured into the tank:
- Alejandro: [tex]\( \frac{41}{15} \)[/tex]
- Anthony: [tex]\( \frac{17}{15} \)[/tex]

[tex]\[ \text{Total water poured} = \frac{41}{15} + \frac{17}{15} = \frac{41 + 17}{15} = \frac{58}{15} \][/tex]

5. Convert the total capacity of the tank into an improper fraction:
- Tank capacity: 8 liters
[tex]\[ 8 = \frac{8 \times 15}{15} = \frac{120}{15} \][/tex]

6. Calculate the water still needed to fill the tank:
[tex]\[ \frac{120}{15} - \frac{58}{15} = \frac{120 - 58}{15} = \frac{62}{15} \][/tex]

7. Convert [tex]\( \frac{62}{15} \)[/tex] to a mixed number:
[tex]\[ \frac{62}{15} = 4 \frac{2}{15} \][/tex]

Therefore, the tank still needs [tex]\( 4 \frac{2}{15} \)[/tex] liters of water to be filled completely. The correct answer is:

b) [tex]\( 4 \frac{2}{15} \)[/tex]