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 580605: If a student had walked 1km/hr faster, he would have taken 15 minutes less to walk 3 km. Find the rate at which he was walking.

Click here to see answer by dfrazzetto(283)

Question 581075: What is the value of 10/7b if b = 2/5?
Click here to see answer by rfer(16322)

Question 581369: d^2+15d+44
Click here to see answer by nerdybill(7384)

Question 581929: How would you x so that x, x+2, and x+3 are consecutive terms of a geometric sequence and find the common ratio r of the sequence.
Click here to see answer by stanbon(75887)

Question 582136: A laptop manufacturer finds that the average time it takes an employee to load a laptop with software is 35 minutes with a standard deviation 15 minutes. Suppose you take a random sample of 64 employees. The standard deviation of the sample mean is:
Click here to see answer by stanbon(75887)

Question 583269: I don't know what category this goes on(so I'm sorry but) I have a problem
Marria read 1/4 of her book on Monday and read the rest on Tuesday. She read 80 more pages on Tuesday and Monday. What was the total pages in Marria's book
Click here to see answer by josmiceli(19441)

Question 583543: what is the 10th,20th,and 30th terms of
1.)3,14,25,36,47
2.)25,38,51,64,77

Click here to see answer by Edwin McCravy(20056)

Question 583554: consider the sequence 2,5,26,677,...determine the recursive formula
Click here to see answer by KMST(5328)

Question 583785: i need to revise sequinces and algerbra for my test TOMMOROW and i cant find a good website for it. do you know any websites or anything to help me revise, by the way im in ks3. please help now thank you
Click here to see answer by Edwin McCravy(20056)

Question 583415: Can you help me figure out what the formula is in this pattern: 8,24,72,216 ? Example of formula:3n-3 N=the position of the number
Click here to see answer by KMST(5328)

Question 584195: What is the arithmetic mean between 85-95?
Click here to see answer by JBarnum(2146)

Question 584747: my car gets 18 miles/ gallon
if driving 194 miles, how many gallons of gas will i need
Click here to see answer by Edwin McCravy(20056)

Question 584818: My grade in a certain math class is determined by three tests. My highest test score will count for 50%
of my grade and my lowest for 20%; the "middle" test score will count for 30%. I must have a weighted
average of 60 in order to pass the class. If I have already earned scores of 70 on my first two tests,
what is the lowest score I can earn on the third test for which I will still pass the class?
Click here to see answer by richwmiller(17219)

Question 584882: Find the common ratio
2 12 72 432
Click here to see answer by jim_thompson5910(35256)

Question 584884: Given a term in a arithmetic sequence and the common difference find the explicit formula
a12=30 d=6
Click here to see answer by jim_thompson5910(35256)

Question 585046: ther were 20 people in the house each shake one another. how many hand shakes took place
Click here to see answer by stanbon(75887)

Question 584771: provide a simple formula or rule that generates the terms of 21,2001,20001,200001.
Click here to see answer by scott8148(6628)

Question 584773: provide a simple formula or rule tat generates the terms of 15,8,1,-6,-13,-20,-27.
Click here to see answer by scott8148(6628)

Question 584779: determine the recursive formula of 1,6,15,28,...
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Question 584796: find the recursive formula of 1,5,12,22,...
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Question 585320: find the terms a2 a3 a4 and a5 of a geometric sequence if a1=10 and the common ratio r=-1
Click here to see answer by Schaman_Dempster(26)

Question 585287: A firm starts work with 110 employees for the first week. The number of the employees rises by 6% per week. How many persons will be employed in the 20th week if the present rate of expansion continues.
I've tried using Sn=a(r^n - 1)/r^n-1 but can't get the right answer.
Click here to see answer by ankor@dixie-net.com(22740)

Question 585632: if a geometric sequence is 80, -40 , 20 . what are the next three terms ?
Click here to see answer by jim_thompson5910(35256)

Question 585639: how do you find the recursive formula of the sequence 1,1,2,3,5,8...?
Click here to see answer by jim_thompson5910(35256)

Question 586294: Which number comes next in this series: 1/2, 1/4, 1/3, 1/6, 1/5, ?
Click here to see answer by Edwin McCravy(20056)

Question 586731: I need an explicit formula for the sequence : {2, 6, 12, 20} I have noticed that the pattern is +4, +6, +8 and so on, but I can't figure out how to write the formula.
Click here to see answer by ad_alta(240)

Question 586739: find the nth term (please explain how)
1, 1/4 , 1/9 , 1/16 , 1/20

Click here to see answer by ad_alta(240)

Question 587333: i dont even know where to start with this problem. -1 < (9-12x)/7 < 8

Click here to see answer by Alan3354(69443)

Question 587377: two numbers with a sum of 10 find the algebaric expression
Click here to see answer by abush(5)

Question 588098: Find the pattern for the following series of numbers:
8, 5, 4, 9, 1, 7, 6, 3, 2, 0.

Hints: This series problems looks just like a normal series problem, but it is different. You must get "out of the box" and use your right brain to solve this one. Note, too, that the series ends with the last digit, as indicated by the period (.). Also, the answer is not that it is a random arrangement of the first 10 numbers (0 - 9) in the number system.
Click here to see answer by ankor@dixie-net.com(22740)

Question 588275: State whether the following sequences are arithmetic; and if so, state the common difference.
15, 18, 21, 24

Click here to see answer by Edwin McCravy(20056)

Question 588204: Please help me solve this:
Each one has 2 parents, 4 grandparents, and 8 great grandparents. etc. How many ancestors has each one had in the last 10 generations?
Click here to see answer by ankor@dixie-net.com(22740)

Question 588853: Find the first four Terms in the sequence
A=An-1+10 if A1=29
Click here to see answer by jim_thompson5910(35256)

Question 589332: what is the sequence of 1/2,1,3/2,
Click here to see answer by stanbon(75887)

Question 589502: Please help me solve this.
Find the formula for the general term of the sequence, starting from n=1.
1/2, 3/4, 5/6, 7/8,...
Click here to see answer by stanbon(75887)

Question 589466: For the sequence, describe the pattern, write the next term, and write a rule for the nth term.
-2,05,-8,-11,...
Click here to see answer by KMST(5328)

Question 589507: Please help me solve this problem.
Use the ratio test to determine whether the series define in the following is converge or diverge.
∞
∑ 1/k!
k=1

Click here to see answer by Edwin McCravy(20056)

Question 589906: i am really strugling with my algerbric sequnces homework could you help me
Click here to see answer by solver91311(24713)

Question 590429: How do I prove the following sequence is geometric?
tn = 24 x (-1/2)n-1
Click here to see answer by Theo(13342)

Question 591561: You are the owner of an apartment building that is being offered for sale for $1,500,000. You receive an offer from a prospective buyer who wants to pay you $500,000 now, $500,000 in 6 months, and $500,000 in 1 year.
a. What is the actual present value of this offer, considering you can earn 12% interest compounded monthly on your money?
b. If another buyer offers to pay you $1,425,000 cash now, which is a better deal?
c. Because you understand the "time value of money" concept, you have negotiated a deal with the original buyer from part a, whereby you will accept the three-payment offer but will charge 12% interest, compounded monthly, on the two delayed payments. Calculate the total purchase price under this new agreement.
d. Now, calculate the present value of the new deal, to verify that you will receive the original asking price of $1,500,000 for your apartment building.
Click here to see answer by Theo(13342)

Question 591705: The sum of three consecutive odd integers is 33 What is the product of the least and greastest intenger ?

Click here to see answer by Alan3354(69443)

Question 591828: Use inductive reasoning to predict the next number in the sequence. 3, 10, 17, 24, 31
Click here to see answer by jim_thompson5910(35256)

Question 593818: the first term of a sequence is -6, and every term after the first is 8 more than the term immediately preceding it. what is the value of the 101st term?
Click here to see answer by scott8148(6628)

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