Hello,
[tex] t_{2}=t_{1}*q\\
t_{3}=t_{2}*q=t_{1}*q^{2}\\
...\\
t_{5}=t_{1}*q^{4}\\
t_{8}=t_{1}*q^{7}\\\\
\dfrac{3}{24}= \dfrac{1}{8}=\dfrac{t_{8}}{t_{5}}= \dfrac{t_{1}*q^{7}}{t_{1}*q^{4}}=q^{3}\\
q= \frac{1}{2} \\
t_{6}=t_{5}*q=24* \dfrac{1}{2}=12\\
[/tex]
