Questions on Algebra: Sequences of numbers, series and how to sum them answered by real tutors!

Tutors Answer Your Questions about Sequences-and-series (FREE)

Question 925521: find the arithmetic mean and fill in the blanks.
32,__,__,__,68,...
Click here to see answer by Edwin McCravy(20056)

Question 926679: Hello,
I am having a hard time writing the explicit and recursive formula/expression for the sequence 12,6,3,1.5. I have tried solving for the explicit formula by plugging in a 12(1/2)(x-1) and 12(1/2)x in my calculator but I seem to always have trouble setting up the formula in the right way. I feel like once I get the explicit then it will be simple to get the recursive. Thank you!!!
K. Legters
Click here to see answer by richard1234(7193)

Question 926824: Write an expression for the calculation double the number 6 and then subtract 36 by 12

Click here to see answer by MathLover1(20850)

Question 926911: {sn}={n^2-n}
Click here to see answer by Edwin McCravy(20056)

Question 926911: {sn}={n^2-n}
Click here to see answer by Alan3354(69443)

Question 926763: -1,4,21,56,... ?
Click here to see answer by Edwin McCravy(20056)

Question 926926: Which of these values for the number of ounces in a pound is most accurate, when compared to the exact value?
20, 15, 6 , 10
Click here to see answer by MathLover1(20850)

Question 927186: Goran's gas tank is 1/4 full. After he buys 10 gallons of gas, it is 2/3 full. How many gallons can Goran's tank hold?
Click here to see answer by CharlesG2(834)

Question 927432: a1=3;d=6an=;a15=
Click here to see answer by ewatrrr(24785)

Question 927495: an auditorium has 50 rows of seats. There are 8 seats in the first row, 10 seats in the second row, 12 seats in the third row, and so on. How many seats are in the auditorium
Click here to see answer by josmiceli(19441)

Question 927481: What is the number missing in the sequence below?
4,7,11,17 (), 39
is it 26?
4+2=6
7+2=9
11+2=13
then,
7+4=11
11+6=17
17+9=26
26+13=39
is this correct?
Click here to see answer by richard1234(7193)

Question 927457: find the fifth term an nth term of the geometric sequence a=9;r=3
Click here to see answer by srinivas.g(540)

Question 927486: What is the missing number in the sequence below?
4,7,12,21, (), 71
Click here to see answer by srinivas.g(540)

Question 927462: I need to know what number comes next in the following sequence 1 1 3 2 4 6 5 25?
Click here to see answer by srinivas.g(540)

Question 927484: What is the number missing in the sequence below?
5,13,23,37, (), 97
Click here to see answer by srinivas.g(540)

Question 927582: How many terms are in the series,
a) 26 + 20 + 14 +....+ tn if its sum is -240?
b)4 + 12 + 36 +...+ tn if its sum is 39 364?

Click here to see answer by jim_thompson5910(35256)

Question 927581: Find the sum of the series 5 + 20 + 80 + ....+ 20 480

Click here to see answer by MathLover1(20850)

Question 927690: 28,35,?,77 number in place of question mark
Click here to see answer by KMST(5328)

Question 927794: Write down a recursive definition of the geometric sequence that has 1st term a and common ratio r. (Be sure your definition is recursive!)
Click here to see answer by Edwin McCravy(20056)

Question 927793: An arithmetic sequence has 1st term 6 and common difference 624. A geometric sequence has 1st term 2 and common ratio 3. Determine an n so the nth term of the arithmetic sequence is the same as the nth term of the geometric sequence.

Click here to see answer by stanbon(75887)

Question 927791: Find the 1st term of the arithmetic sequence with 11th term −1 and 21th term 7.
Click here to see answer by josgarithmetic(39618)

Question 927791: Find the 1st term of the arithmetic sequence with 11th term −1 and 21th term 7.
Click here to see answer by MathTherapy(10552)

Question 927792: There are two geometric sequences with 3nd term 5 and 5th term 80. What are the two possible values of the 4rd term?
Click here to see answer by stanbon(75887)

Question 927792: There are two geometric sequences with 3nd term 5 and 5th term 80. What are the two possible values of the 4rd term?
Click here to see answer by MathTherapy(10552)

Question 928295: If you charge group one $3 per person, and group two $5 per person, and 63 people participated, and a total of $231 was collected, then how many people from each group participated?
Click here to see answer by TimothyLamb(4379)

Question 929202: is this sequence arithmetic, geometric, or neither?
24, 30, 36, 42, . . .

Click here to see answer by Alan3354(69443)

Question 929332: please help me find the sum of the following sequence (-6)+(-1)+4+9+...+39 thank you
Click here to see answer by Fombitz(32388)

Question 929332: please help me find the sum of the following sequence (-6)+(-1)+4+9+...+39 thank you
Click here to see answer by KMST(5328)

Question 929347: please help me solve the following: determine whether the infinite geometric series converges or diverges. Find its sum
5-5/3+5/9-5/27+... thank you
Click here to see answer by ewatrrr(24785)

Question 929402: How is the nth term of decreasing sequences solved?

Click here to see answer by richard1234(7193)

Question 929619: what is the 52 term for the sentence pattern?: 7, 10, 13, 16, 19, 22
Click here to see answer by ewatrrr(24785)

Question 929822: answer for what is the sixteen term in the following sequence? 1,2,4,7,11,16,22
t1=1, t2=2
Difference between the two sequence is greater than one from the differnce between the previous two section
Click here to see answer by Edwin McCravy(20056)

Question 929771: A three digit number with respective digits from left to right of SSS is added to a three digit number with respective digits from left to right of TTT, and the sum is a four digit number with respective digits from left to right of TTTR. Find the value of the digit S.
I would appreciate any help!
Thanks!
Click here to see answer by Edwin McCravy(20056)

Question 930287: 5-7-2-12-9-6-56- what number comes next and how?
Click here to see answer by Edwin McCravy(20056)

Question 930577: The difference between two number is 200.
One number is between 400 and 450.
The other number is more than 200 but less than 210
What are the possible number?
Click here to see answer by Edwin McCravy(20056)

Question 929889: I need to find the next number in the sequence but not sure how to get there
3, -6, 12, 4, 20
Answer Choices
13
14
6
16
Click here to see answer by Edwin McCravy(20056)

Question 930614: find the 12th number in the sequence 8, 11, 14, 17, 20....
Click here to see answer by MathLover1(20850)

Question 930745: Hi would you please help me with my homework.
A machine depreciates by 1/4 of its value each year. If it costs $630,000 new, what is its value after 5 years? (Round to nearest dollar)
My professor said the answer is $149,502
Will you please show me the steps on how to solve the problem. Thank you.
Click here to see answer by josgarithmetic(39618)

Question 930752: Hi would you please help me with this homework.
Write a formula for the nth of the following geometric sequence.
-3,3/4,-3/16,3/64...
According to my professor the answer is an=-3*(-1/4)^n-1
Would you please show me the steps on how to solve this problem. Thank you
Click here to see answer by jim_thompson5910(35256)

Question 930749: Hi would you please help me with my homework.
Suppose that an automobile loses 1/5 of its value each year; that is at the end of a given year the value is 4/5 of the value at the beginning of that year. If a car costs $24,000 new, What is the value at the end of five years?
My professor said that the answer is $7864.
Would you please show me the steps on how to solve this problem. Thank you.
Click here to see answer by jim_thompson5910(35256)

Question 930744: Hi I need help with my homework would you please help me. Thank you.
Use the formula for an to find the general term of the arithmetic sequence below.
11,47/4,25/2,53/4...
According to my professor the answer is: 41/4 + 3n/4
Would you kindly please show me the steps on how to solve this problem. Thank you.
Click here to see answer by josgarithmetic(39618)

Older solutions: 1..45, 46..90, 91..135, 136..180, 181..225, 226..270, 271..315, 316..360, 361..405, 406..450, 451..495, 496..540, 541..585, 586..630, 631..675, 676..720, 721..765, 766..810, 811..855, 856..900, 901..945, 946..990, 991..1035, 1036..1080, 1081..1125, 1126..1170, 1171..1215, 1216..1260, 1261..1305, 1306..1350, 1351..1395, 1396..1440, 1441..1485, 1486..1530, 1531..1575, 1576..1620, 1621..1665, 1666..1710, 1711..1755, 1756..1800, 1801..1845, 1846..1890, 1891..1935, 1936..1980, 1981..2025, 2026..2070, 2071..2115, 2116..2160, 2161..2205, 2206..2250, 2251..2295, 2296..2340, 2341..2385, 2386..2430, 2431..2475, 2476..2520, 2521..2565, 2566..2610, 2611..2655, 2656..2700, 2701..2745, 2746..2790, 2791..2835, 2836..2880, 2881..2925, 2926..2970, 2971..3015, 3016..3060, 3061..3105, 3106..3150, 3151..3195, 3196..3240, 3241..3285, 3286..3330, 3331..3375, 3376..3420, 3421..3465, 3466..3510, 3511..3555, 3556..3600, 3601..3645, 3646..3690, 3691..3735, 3736..3780, 3781..3825, 3826..3870, 3871..3915, 3916..3960, 3961..4005, 4006..4050, 4051..4095, 4096..4140, 4141..4185, 4186..4230, 4231..4275, 4276..4320, 4321..4365, 4366..4410, 4411..4455, 4456..4500, 4501..4545, 4546..4590, 4591..4635, 4636..4680, 4681..4725, 4726..4770, 4771..4815, 4816..4860, 4861..4905, 4906..4950, 4951..4995, 4996..5040, 5041..5085, 5086..5130, 5131..5175, 5176..5220, 5221..5265, 5266..5310, 5311..5355, 5356..5400, 5401..5445, 5446..5490, 5491..5535, 5536..5580, 5581..5625, 5626..5670, 5671..5715, 5716..5760, 5761..5805, 5806..5850, 5851..5895, 5896..5940, 5941..5985, 5986..6030, 6031..6075, 6076..6120, 6121..6165, 6166..6210, 6211..6255, 6256..6300, 6301..6345, 6346..6390, 6391..6435, 6436..6480, 6481..6525, 6526..6570, 6571..6615, 6616..6660, 6661..6705, 6706..6750, 6751..6795, 6796..6840, 6841..6885, 6886..6930, 6931..6975, 6976..7020, 7021..7065, 7066..7110, 7111..7155, 7156..7200, 7201..7245, 7246..7290, 7291..7335, 7336..7380, 7381..7425, 7426..7470, 7471..7515, 7516..7560, 7561..7605, 7606..7650, 7651..7695, 7696..7740, 7741..7785, 7786..7830, 7831..7875, 7876..7920, 7921..7965, 7966..8010, 8011..8055, 8056..8100, 8101..8145, 8146..8190, 8191..8235, 8236..8280, 8281..8325, 8326..8370, 8371..8415, 8416..8460, 8461..8505, 8506..8550, 8551..8595, 8596..8640, 8641..8685, 8686..8730, 8731..8775, 8776..8820, 8821..8865, 8866..8910, 8911..8955, 8956..9000, 9001..9045, 9046..9090, 9091..9135, 9136..9180, 9181..9225, 9226..9270, 9271..9315, 9316..9360, 9361..9405, 9406..9450, 9451..9495, 9496..9540, 9541..9585, 9586..9630, 9631..9675, 9676..9720, 9721..9765, 9766..9810, 9811..9855, 9856..9900, 9901..9945, 9946..9990, 9991..10035, 10036..10080, 10081..10125, 10126..10170, 10171..10215, 10216..10260, 10261..10305, 10306..10350, 10351..10395, 10396..10440, 10441..10485, 10486..10530, 10531..10575, 10576..10620, 10621..10665, 10666..10710, 10711..10755, 10756..10800, 10801..10845, 10846..10890, 10891..10935, 10936..10980, 10981..11025, 11026..11070, 11071..11115, 11116..11160, 11161..11205, 11206..11250, 11251..11295, 11296..11340, 11341..11385, 11386..11430, 11431..11475, 11476..11520, 11521..11565, 11566..11610, 11611..11655, 11656..11700, 11701..11745, 11746..11790