Divide -8 from both sides to get the answer
For a geometric sequence
<em>a</em>, <em>ar</em>, <em>ar</em> ², <em>ar</em> ³, …
the <em>n</em>-th term in the sequence is <em>ar</em> <em>ⁿ</em> ⁻ ¹.
The first sequence is
1, 3, 9, 27, …
so it's clear that <em>a</em> = 1 and <em>r</em> = 3, and so the <em>n</em>-th term is 3<em>ⁿ</em> ⁻ ¹.
The second sequence is
400, 200, 100, 50, …
so of course <em>a</em> = 400, and you can easily solve for <em>r</em> :
200 = 400<em>r</em> ==> <em>r</em> = 200/400 = 1/2
Then the <em>n</em>-th term is 400 (1/2)<em>ⁿ</em> ⁻ ¹.
Similarly, the other sequences are given by
3rd: … 4 × 2<em>ⁿ</em> ⁻ ¹
4th: … 400 (1/4)<em>ⁿ</em> ⁻ ¹
5th: … 5<em>ⁿ</em> ⁻ ¹
6th: … 1000 (1/2)<em>ⁿ</em> ⁻ ¹
7th: … 2 × 5<em>ⁿ</em> ⁻ ¹
Answer:
Step-by-step explanation:
The $50 cleanup fee is a "fixed cost."
The "$30 per-person fee is a "variable cost." That is, it varies with the number of people.
"within" means "less than or equal to"
Cost = $50 + $30x [where x = number of people]
Cost ≤ $4500 ["stay within their budget"]
$50 + $30x ≤ $4500 [substitute for cost]
$30x ≤ $4450 [subtract $50 from both sides retains sense of inequality]
x ≤ 148.3333 [divide by +$30 retains sense of inequality]
Mark and Heather may invite up to 148 guests.
[note: to be "≤," always truncate, never round up]
Check:
148 people for $30 each + $50 is $4440+$50 = $4490.
One more person makes it $4520 -- that is too much.
There we go, my bad