Answer:
130
Step-by-step explanation:
A standard deviation is 15, so 2 standard deviation is 30, 2 standard deviations above 100 is 100+30=130
Answer:
![\Sigma_{k=1}^{n}[3(\frac{10}{9} )^{k-1}]](https://tex.z-dn.net/?f=%5CSigma_%7Bk%3D1%7D%5E%7Bn%7D%5B3%28%5Cfrac%7B10%7D%7B9%7D%20%29%5E%7Bk-1%7D%5D)
Step-by-step explanation:
A geometric sequence is a list of numbers having a common ratio. Each term after the first is gotten by multiplying the previous one by the common ratio.
The first term is denoted by a and the common ratio is denoted by r.
A geometric sequence has the form:
a, ar, ar², ar³, . . .
The nth term of a geometric sequence is 
Therefore the sum of the first n terms is:

Given a geometric series with a first term of 3 and a common ratio of 10/9, the sum of the first n terms is:
Answer:
198
Step-by-step explanation:
2(9)(11)
Since you know that r = 9 and t = 11, you can substitute the variables to numbers. Then you just multiply to get 198. Hope this helps :)
Answer:
7/20:1/4:2/5
Step-by-step explanation:
Answer:
2.9 mi
Step-by-step explanation:
The time difference t between 12.30pm and 3.30pm is 3h.
Let the distance to Marat's house be s.
The equation to calculate velocity v is given by:
v = distance / time.
Now you can write an equation for the time difference t and use the two velocities and the 90 min(= 1.5h) she stays:
3 = s/12 + 1.5 + s/2.3
Solve this equation for s:
(1/12 + 10/23)* s = 1.5
s = 2.9