ANSWER
The volume at the end of one week will be 22.32 liters.
EXPLANATION
If the balloon with a small leak loses 1% of its volume each day, then by the end of one week, it will lose 7℅ of its volume.
If the balloon originally contains 24 liters of gas, then this corresponds to 100%.
The volume at the end of one week will correspond to (100-7)%=93%
The volume at the end of one week is
[tex] = \frac{93}{100} \times 24[/tex]
[tex] = \frac{2232}{100} [/tex]
[tex] = 22.32 \: liters[/tex]