C
the sum to infinity of a geometric series = 
where a is the first term and r the common ratio
=
= 81 × 3 = 243

and you know what that is.
Answer:
31
Step-by-step explanation:
<span>Well, they couldnt have studied negative time.. So Id say the domain is \(x \ge 0\) where \(x\) is the time they studied.</span>
Answer:
5:3
Step-by-step explanation:
When the ratio says x:y=5:1, it means that x is 5 times greater than y. So, plug in 5 for x and 1 for y.
4(5)+5(1):3(5)
20+5:15
25:15 , if simplified then the ratio 5:3