Answer:
Let $y$ be the younger turtle's age today. Then the older turtle's age today is $11y.$ So $24$ years from now, the younger turtle's age will be $y+24$ and the older turtle's age will be $11y+24.$ However, we know the older turtle's age will be $7$ times that of the younger turtle then, which tells us that
\[11y+24=7(y+24).\]Distributing, we get $11y+24=7y+168.$ Subtracting $7y+24$ from both sides of this equation, we get $4y=144,$ so $y=36.$
This is the younger turtle's age today, but that's not what we're looking for in this problem - we're looking for the number of years from today that the older turtle's age will be triple that of the younger turtle. Let $k$ be this number of years. Since the younger turtle's age today is $y=36$ and the older turtle's age today is $11 \cdot 36=396,$ it follows that $k$ years from now my turtles' ages will be $36+k$ and $396+k$ respectively. Since we want to know when the older turtle's age will be triple that of the younger turtle, we want to know for what $k$ this equation will be true:
\[3(36+k)=396+k.\]Distributing, we get $108+3k=396+k.$ Subtracting $k+108$ from both sides of this equation, we get $2k=288.$ Therefore, $k=\boxed{144}.$
Explanation: