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 957117: Determine if the sequence is geometric. If it is, find common ratio and 8th term.
1,9,25,49
Click here to see answer by amarjeeth123(569)

Question 957196: if we list all the natural numbers below 10 that are multiples of 3 or 5, we get
3, 5, 6 and 9. The sum of these multiples is 23. Find the sum of all the
multiples of 3 or 5 below 2812.
Click here to see answer by Edwin McCravy(20056)

Question 957274: Which is the eighth term in the sequence: a(base)n= - 1/25 (5^(n-1))

A. -3125
B. -125
C. -625
D. -25
Click here to see answer by stanbon(75887)

Question 957290: What is the sum of the first five terms of a geometric series with a1=10 and r=1/5?
Click here to see answer by jim_thompson5910(35256)

Question 957331: which number comes after 86
Click here to see answer by smcowell_(5)

Question 957473: if "n" arithmetic means�were�inserted between 75 and 19 such that the sum of the third and the fourth means to the sum of the means whose order are (n-3)�and (n-4) equals 61: 37 evaluate n. .... I know that n equals 13 but i don't know how
Click here to see answer by KMST(5328)

Question 957478: write a formula for then term of the sequences 0 3 8 15 24 35
1 1/2 1/4 1/8 1/16.....
Click here to see answer by KMST(5328)

Question 957478: write a formula for then term of the sequences 0 3 8 15 24 35
1 1/2 1/4 1/8 1/16.....
Click here to see answer by stanbon(75887)

Question 957536: there are two numbers x and y such that x >y. their gcf is 4 and lcm is 48.if 2 is added to y the hcf is increased by 2.if 2 is subtracted from x the hcf is reduced by 2. find values of x and y.
Click here to see answer by mahender303@gmail.com(1)

Question 957525: , what happens to the sum when r=1?
Click here to see answer by satyareddy(3)

Question 957592: If the first 3 items of a geometric progression are a − 1, a +3, and 3 a +1 for some positive
number a, what is the numerical value of the fourth term?
Click here to see answer by MathLover1(20850)

Question 957648: What must the missing piece of data be to have a mean of 33 if the numbers are 30,37, and 23?
Click here to see answer by josgarithmetic(39617)

Question 957753: The distance that a spring will stretch varies directly as the force is applied to the spring. A force of 70 pounds is needed to stretch a spring 7 inches. What force is required to stretch the spring 13 inches?
Click here to see answer by macston(5194)

Question 957770: Hi there, Im looking to find the sum of the first four terms of this sequence
-18,9,-9/2
Click here to see answer by macston(5194)

Question 957953: The next two terms of the sequence -1, 2, 12, 40? Please explain how you solve it. Thanks in advance
Click here to see answer by macston(5194)

Question 958121: Hello, I'm having a hard time with turning word problems into equations. I keep getting them wrong. Please help me to understand.
Here is the problem: the difference of two numbers is 8. Five times the smaller number equals the greater number. Find the numbers.
From what I understand, the difference means x - x = 8 (8 is the difference)
Let 5x = smaller number
Greater - x
So: 5x - x = 8
But my answer is wrong. It said the right answer is 5x = 8 + x
But i dont get it? If it's addition why did the problem use the word "difference " please help.

Click here to see answer by MathTherapy(10552)

Question 958214: what is the next number and how did you arrive at it? 7,16,8,27,9, is the answer 27 or 10 or 40 or 37
Click here to see answer by macston(5194)

Question 958217: What is the value of the expression ?

A.-1
B.0
C.17
D.69
Click here to see answer by macston(5194)

Question 958413: Hello, I've been struggling with forming equations from word problems. I love math but word problems are my weakness, I've been stuck here trying to figure out the equations for days. My heads already hurting, please help me understand.
The word problem is: the sum of three numbers is 50. The second number is three times the first number, and the third number is twice the second number. What are the numbers?
(I know how to solve equations, i just don't know how to form equations using word problems. )
Click here to see answer by josmiceli(19441)

Question 958425: 27,64,125,216,343,?
Click here to see answer by Alan3354(69443)

Question 958411: Please help to solve below problem..
1.5d-13 is an odd number what is 7th even number coming after it.
2.x-7 is an odd number what is 17 even number prior to that number.
Click here to see answer by rothauserc(4718)

Question 958539: Hi,
I understand how to find the rule when the ratios are whole numbers, but I'm having trouble with the fractional ratios.
Here's the question:
Find the possible explicit rule for the nth term of the sequence.
5,.5,.05,.005,...
Thank you in advance!
Click here to see answer by stanbon(75887)

Question 958579: Find the possible explicit rule for the nth term of the sequence, then find the 10th term.
1, -.5, 1/3, -1/4, 1/5,...
Thank you in advance!
Click here to see answer by Fombitz(32388)

Question 958597: Given two terms of the arithmetic sequence, a7=12 and a10=-9, find a1 and d.
Click here to see answer by Fombitz(32388)

Question 958972: 4. Suppose a = 112, b = 80, and c = 68 in the ∆ABC as shown in the
figure at the right. What is the approximate measure of ∠C? a. 20�
b. 98�
c. 37�
d. None of these

Click here to see answer by josgarithmetic(39617)

Question 958702: 1,3,9,15,25,35....
find tenth term
Click here to see answer by Edwin McCravy(20056)

Question 959015: The 31st term of an AP whos first two terms are respectivly -2 and -7 is...
Click here to see answer by Fombitz(32388)

Question 959119: A student takes 2 pages of notes during each hour in class. How many pages of notes will he take during 13 hours of class?
Click here to see answer by stanbon(75887)

Question 959118: Write the series with summation notation: 2+5+8+11+...
Click here to see answer by stanbon(75887)

Question 959118: Write the series with summation notation: 2+5+8+11+...
Click here to see answer by jim_thompson5910(35256)

Question 959184: What are the next four terms in the following arithmetic sequence? -7, -2, 3, 8, �
Click here to see answer by Fombitz(32388)

Question 959187: Find the four arithmetic means between 100 and 135.
Click here to see answer by Alan3354(69443)

Question 959186: Find the four arithmetic means between -21 and -36.
Click here to see answer by Alan3354(69443)

Question 959183: What is the d value in the following arithmetic sequence? -7, -2, 3, 8,...

Click here to see answer by josgarithmetic(39617)

Question 959185: What is the 25th term in the following arithmetic sequence? -7, -2, 3, 8, ...
Click here to see answer by josgarithmetic(39617)

Question 959206: what is the sequence of 2,9,16,27 and then what is the recursive rule for the nth number and explicit rule?

Click here to see answer by Edwin McCravy(20056)

Question 937593:
I wrote out a general solution here . . . https://www.scribd.com/doc/260182194/Elementary-Sequences
Click here to see answer by acubed1234(5)

Question 959686: What's 9 times x equals 405

Click here to see answer by EdenWolf(517)

Question 959740: The sum of three consecutive numbers is117 what is the smallest of the three numbers?
Click here to see answer by Alan3354(69443)

Question 959558: Can you find the sum of the first 60 terms in the series 2+6+4+12+6+24
Click here to see answer by Edwin McCravy(20056)

Question 959425: find the smallest term of the geometric progression 5,5,8 1/3...... that exceeds 100
Click here to see answer by Edwin McCravy(20056)

Question 959198: find the closed form of the sequence (start from n=1)
2,1,2,5,15,52,203,877

Click here to see answer by Edwin McCravy(20056)

Question 952539: 5 10 3 15 20 13 25 30 __
Click here to see answer by Edwin McCravy(20056)

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