math
posted by Jon
Hi I need someone to check my answers I'll show whatever work I have but for time purposes I'll just post my answers because I think I have most of them correct. Thanks!
1)Find the 20th term of the arithmetic sequence in which a1=3 and d=7.
A)143
B)136
C)140
D)133
I chose B
2)Write an equation for the nth term of the arithmetic sequence 3,3,9,15...
A)aN=n+6
B)aN=6n+9
C)aN=6n9
D)aN=n3
I chose B
3)Find the two arithmetic means between 4 and 22.
A)10,16
B)8,16
C)8,12
D)13,13
I chose A
4)Simplify: Find Sn for the arithmetic series in which a1=3,d=1/2,and aN=15
A)225
B)9
C)45
D)210
I chose B
5)ok this one's tricky to type but its with sigma so here it is.
There is a sigma sign and there is an 8 on the top of it and k=3 below. In parentheses to the right is (403k) and the question is Find.
A)45
B)282
C)90
D)141
I chose D. this question is tricky but if you read it slowly and you know about sigma you'll be able to help. Thanks again.

Reiny
Your #2 and 4 are not correct
#2:
you picked B which is t_{n} = 6n+9
if you let n=1 you get 15 as your first term, you should obtain 3
doesn't C give you that result?
#4:
t_{n} = 15
15 = 3 + (n1)(1/2)
12 = (n1)/2
24 = n1
n=25
So S_{25} = 25/2[6 + 24(1/2)]
= 25/2[18]
= 225 which is A 
Jon
ok thanks. Did you check the others?

Reiny
the others were ok
Respond to this Question
Similar Questions

math
I know youall are very busy an that answering posts takes time, but I am in real need of some one to check my questions to see if they are correct, because I need to post my answers very SOON!! PLEASE HELP!!!! THANKS!! 
Calculus (pleas help I really need to check this)
Assume that each of the follwing functions gives the position of an object at time t. Find the velocities indicated by setting up and evaluating a limt algebraically. (a) s(t) = 3t^2, Find v(1). (b) s(t) = 1/t , Find v(2). (c) s(t) … 
To Sam: Penn Foster answers
Please do not post any more answers. Jiskha is not a repository for any exam answers. In addition, we have no idea what the questions are. If you want to post a couple of your exam questions along with your answers, we'll be glad to … 
PreCalc
1) Determine the value of r (put this number in the first blank) and then determine the value of the 10th term of the geometric sequence. Do not use any decimals or mixed numbers in your answers. Reduce all fractions to lowest terms. … 
Math ( Can You check my Work?)
1.an = 3n  1 2. an = 2(2n  3) 3.an = 4^n 4.an = (2/3)^n 5. an = (1)^n(n + 5) 6. an = (1)^n + 1(n + 6) 7. an= n+3/2n1 8. a1 = 5 and an = an1  3 for n ≥ 2 9. a1 = 6 and an = 2an1 for n ≥ 2 10.a1 = 4 and an = 3an1 … 
physics
A pair of sleds weighs 25kg and experiences a frictional force of 25N. If a dog team applies a 175N force pulling it 12m. 1. Find the work done by friction 2. Find the work done by the dog team 3. Find the net work done I need to compare … 
Grammar
Tranformation of Sentences ? 1.He wont show me his papers,he wont tell me who he is (use neither nor) 2.This is all i posses.(Turn to negative) 3.No man in tge street came forward to help her.(Turn to Assertive) Plz post in the answers 
Math
There are six truefalse questions on a quiz. Not knowing any of the answers, a student guesses randomly. Find the probability of each event. Exactly two answers are correct. Exactly six answers are correct. At least five are correct. … 
Math
Hi I did a quiz today it said I got A 5/9 but it did not show me the correct answers or the ones i missed so if it could be possible that someone could the answers so I could see which ones I need to fix please help me I just came … 
@ Sarah  econ
I deleted your 43(!) questions. Since you didn't post your answers, I assume you wanted someone else to cheat and give you the answers. No way! If you try that again, you'll be banned from posting here! If you want to post three or …