Let
be the n'th term of the sequence.
so
is the first term,
the second term and so on...
In a geometric sequence with
, and common ratio r, the terms are as follows:
.
.
that is, each term is its previous term times the common ratio r.
In our example
and
so
Answer: r=0.75
Answer:
my answer is definitely elementary statistics
Answer:
a68 = -85.2
Step-by-step explanation:
The formula for an arithmetic sequence is
an = a1+d(n-1)
a1 =8.6 (it is the first term)
We can find the common difference by taking the second term and subtracting the first term
7.2-8.6 =-1.4
d=-1.4
n = the term number we are looking for
an = 8.6 -1.4(n-1)
We are looking for the 68th term so n=68
a68 = 8.6 -1.4(68-1)
= 8.6 -.1.4(67)
= 8.6-93.8
=-85.2
D=distance traveled one way
t=d/s
d/20 + d/30 = 12
3d+2d=60(20)
5d=720
d=720/5 = 144 mi one way
144/20 = 7.2 hrs at 20 mph
144/30 = 4.8 hrs at 30 mph