Ok...
We know that when: t=0, C(t)=8.
With this data, the expression below can be produced...
8=ab⁰
Now since b⁰=1, we've discovered that a=8.
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Furthermore, we also know that when: t=1, C(t)=24. Since we discovered that a=8, we can produce the expression below...
24=8*b¹
This means that:
8b=24
Therefore: b=24/8=3.
If a=8 and b=3...
C(t)=8*(3^t)
Answer:
C(t)=8*(3^t)