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 1105787: What series of number comes after
211619,687009,201438,215845,309412,442876,657205,_?
Click here to see answer by ikleyn(52787)

Question 1105932: What is the total pay for a person that is paid 1 cent on the first day and 2 cents on the second day and it doubles each day after for the 30 days?
Click here to see answer by Alan3354(69443)

Question 1105930: Check the formula summation n^2 = ((k)(k+1)(2k+1))/6 when n=0, to k is correct when k= 1,2, and 3.

Click here to see answer by ikleyn(52787)

Question 1106280: What is the number that comes next in the sequence
8,380,8,290,8,200; ?
Click here to see answer by josgarithmetic(39617)

Question 1106281: What is the mode in this list of numbers?
17,7,31,29,17,4,11,4
Click here to see answer by Edwin McCravy(20056)

Question 1106395: 1) Find three numbers in G.P. Whose sum ir 13 and the sum of whose squares is 91.
Click here to see answer by greenestamps(13200)

Question 1106455: Determine the sum of the first 15 terms of an arithmetic series if the middle term is 92.
Click here to see answer by rothauserc(4718)

Question 1106490: Three numbers are in the ratio 3:9:10. If 10 is added to the last number, then the three numbers form an arithmetic progression. What are the three numbers?

Click here to see answer by josgarithmetic(39617)

Question 1106491: In the arithmetic series, if S_n = 5n^2+4n, find the first three terms.
So the first term is 9, and I tried using the formula S_n= (a1+an)/2 * n
I got confused... does an = 5n^2+4n
Click here to see answer by ikleyn(52787)

Question 1106547: In each group, find the pattern and write down the missing number
[8, 6, 16] [9, 3, 3] [15, ?, 13]
[5,10,5] [8,14,10] [?,11,7]
4 $ 1= 2
5 $ 3= 5
9 $ 4= 10
3 $ 2=?

Click here to see answer by greenestamps(13200)

Question 1106618: What comes next in the sequence 2,3,7,23,?
Click here to see answer by Edwin McCravy(20056)

Question 1106618: What comes next in the sequence 2,3,7,23,?
Click here to see answer by Alan3354(69443)

Question 1106618: What comes next in the sequence 2,3,7,23,?
Click here to see answer by ikleyn(52787)

Question 1106778: 3, -6, 12, 4, 20
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Question 1106814: Find the ninths term of the geometric progression 2, 2√3, 6,...
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Question 1106813: Insert three geometric means between 1/9 and 27
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Question 1106812: Find the sum of the first ten terms of the geometric series 2-1+�-�+...
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Question 1106829: What is the next number in the sequence
7, 21, 8, 72, 9
Click here to see answer by greenestamps(13200)

Question 1106827: What is next number in sequence
2, 7, 26, 101, 400
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Question 1106886: 5,10,30,60,180,
Click here to see answer by josgarithmetic(39617)

Question 1106885: 1 + 2 = 3
4 + 5 + 6 = 7 + 8
9 + 10 + 11 +12 = 13 + 14 +15
What would the last number of the 16th equation
Click here to see answer by greenestamps(13200)

Question 1106995: The sum of four numbers in arithmetic progression is 16. The square of the last number is the square of the first number plus 48. What are the four numbers?
Click here to see answer by josgarithmetic(39617)

Question 1107066: The nth term of a linear sequence is 12-4n. find
1.first term
2.common difference
Click here to see answer by stanbon(75887)

Question 1107163: Find the sum of the following geometric series:
2 + 4 + 8 + �+ 256
Click here to see answer by ikleyn(52787)

Question 1107165: find the two possible values of p if p-3,3p+5 and 18p-5 are 3 consecutive terms of a GP
Click here to see answer by ikleyn(52787)

Question 1107201: If the geometric mean of 0.25 or 1 over 4, and 4 is x+3, find the possible values of x.
Click here to see answer by ikleyn(52787)

Question 1107203: The general term of Un of a series is defined by the relation Un+1=0.3*(1+Un). n is greater than or equal to 1 and U1 =1. Calculate U2, U3 and U4.
A second series is defined with the general term Vn, by the relation Vn=Un - 0.5 n is greater than or equal to 1.
Show that this series(Vn) is an exponential series.
Express Vn and hence Un as function of n.
Click here to see answer by stanbon(75887)

Question 1107227: In an arithmetic series, t5=16 and S10=175, find S25
Click here to see answer by ikleyn(52787)

Question 1107236: what is the value of 9^(1/3) x 9^(1/9) x 9^(1/27) x ...?
also is there a general formula in solving these types of question? thanks!
Click here to see answer by KMST(5328)

Question 1107256: 3;5;11;21
Determine the value of the 48th term

Click here to see answer by Boreal(15235)

Question 1107256: 3;5;11;21
Determine the value of the 48th term

Click here to see answer by math_helper(2461)

Question 1107363: A rose garden has 21 bushes in one row, 17 bushes in the next row, then 13, and so on. If there are 66 bushes in the garden, in how many rows are they planted?
Click here to see answer by ikleyn(52787)

Question 1107625: The sum of two numbers is 207.The difference between them is 33.
Find the two numbers.
Click here to see answer by Boreal(15235)

Question 1107651: 97, 63, 18, ..... What is the next in this set of numbers?
Click here to see answer by greenestamps(13200)

Question 1107705: A student calculated an answer to be 50. However, the calculation the student did was multiplication by 3/8 instead of division by 3/8. What is the correct answer?
Click here to see answer by ankor@dixie-net.com(22740)

Question 1107811: how would I calculate if even possible the next number in a sequence. I have on the following four numbers 831, 328, 864, 880 I've tried every thing I can think of it appears to be simple but I'm beat.
Click here to see answer by Alan3354(69443)

Question 1108113: Insert 4 A.M's between 3 and 23
Click here to see answer by ikleyn(52787)

Question 1108174: find the sum of the first n terms of the arithmetic series
-10+(-5)+0+5+10 n=19

Click here to see answer by ikleyn(52787)

Question 1108288: Hi could you plz help me with this question:
For the arithmetic sequence with t7 = 0.6 and t12 = -0.4, find t20.
Thanks
Click here to see answer by Theo(13342)

Question 1108381: Hi I'm stuck on this question:
On Monday William spends 20mins playing the piano. On Tuesday 25 minutes and on each successive day his playing time increases in the same ratio. How many minutes does he play on Friday?
// I've tried doing the question "the long way" but at school, we're focusing on geometric series hence can you show me how to do this question using relevant formulas from this topic. //
Thankyou in advance

Click here to see answer by greenestamps(13200)

Question 1108437: If the 6th term of an AP is -10 and 10th term is -26. Determine the 15th term of an AP.
Click here to see answer by josgarithmetic(39617)

Question 1108444: Let Sn = 1+2+4+...+2^n-1. Find {n: Sn > 1 000 000}
Click here to see answer by greenestamps(13200)

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