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 622376: What's the first fourth and tenth term of a(n)=-6+(n-1)1/5
Click here to see answer by solver91311(24713)

Question 622854: Question: Guess a simple formula for the sequence that begins: -1, 1/2, -1/3, 1/4, -1/5

Thank you for your help!!
Click here to see answer by Alan3354(69443)

Question 622864: First Question: Find the initial term of the arithmetic sequence with 10th term -1 and 20th term 7. (use initial term a0)

Second Question: There are two geometric sequences with 2nd term 5 and 4th term 80. What are the two possible values of the 3rd term?

I truly appreciate your help!!
Click here to see answer by MathTherapy(10552)

Question 622974: conjecture a formula for the sequence.
3, 5, 11, 21, 43, 85, 171, 341, 683, 1365
Click here to see answer by math-vortex(648)

Question 623099: . List the 6 numbers in the sequence from the formula
Tn= n(n + 1)
-------------
2

for n = 4, 5, 6, 7, 8.

Add your answers to this sequence:
1, 3, 6, _______, ______, ______, ______, ______ . . .

Click here to see answer by fcabanski(1391)

Question 623186: per favore mi potete aiutere perch� non ho capito questo problema:
in un rettangolo una dimensione � il triplo dell' altra e la loro somma misura 120 cm. calcola il perimetro di un triangolo equilatero il cui lato � congruente al doppio della dimensione minore del rettangolo.
grazie mille

Click here to see answer by Alan3354(69443)

Question 623187: in a cercle i have 8 numbers, a mystery number then 26, 6, 21, 1,
36, 16, and 16. What is the mystery number?
Click here to see answer by Earlsdon(6294)

Question 623528: the sum of 2 numbers is 72 while the difference between the numbers is 25. the smaller of the numbers is?
Click here to see answer by lenny460(1073)

Question 623612: pls help us find the next number in the series..
3,15,35,63,99,?
Click here to see answer by Alan3354(69443)

Question 624873: Sarah is twice as old as her youngest brother. If the difference between their ages is 15 years, how old is her youngest brother?

Click here to see answer by ewatrrr(24785)

Question 625243: 2a(x+y)
Click here to see answer by jim_thompson5910(35256)

Question 625243: 2a(x+y)
Click here to see answer by lenny460(1073)

Question 625301: Jason purchased a tent from a wholesaler for $50 and then sold it in his wilderness store for $75. What was his markup as a percentage of his purchase price?
Click here to see answer by jankiz(13)

Question 625297: Find the number that is 1/2 of the way from 1 3/4 to 4 5/12
Click here to see answer by jankiz(13)

Question 625297: Find the number that is 1/2 of the way from 1 3/4 to 4 5/12
Click here to see answer by MathTherapy(10552)

Question 625312: There are 27 nickels, dimes, and quarters in the drawer with a value of $3. How many coins of each type are there if there are three times as many nickels as there are dimes?
Click here to see answer by jankiz(13)

Question 625310: The sum of the digits of a two-digit counting number is 10. If the digits are reversed, the new number is one less that twice the original number. What is the original number?
(please help by showing work.)
Click here to see answer by oscargut(2103)

Question 625311: The motorboat traveled 3 times as fast as the sloop. In fact, the motorboat traveled 48 miles in 2 hours less than it took the sloop to travel 24 miles. How fast did each of them travel? What were the times of each?
Click here to see answer by lwsshak3(11628)

Question 625309: The riverboat can travel 80 miles downstream in 5 hours but requires 8 hours to travel and 48 miles upstream. What is the speed of the riverboat in still water, and what is the speed of the current?
Click here to see answer by lwsshak3(11628)

Question 625304: The speedboat traveled at a speed that was twice as fast as the yacht. The speedboat traveled 240 miles in one hour less than it took the yacht to travel 150 miles. What were the speed and time for both the speedboat and the yacht?
Click here to see answer by Emsley(35)

Question 625299: Use substitution to solve: 4x-27=-28 and 2x+3y=-6
Click here to see answer by Emsley(35)

Question 625307: The cylinder contains 1224 grams of the compound CaSO^4. What is the weight of the oxygen (O) in the compound? (Ca, 40; S, 32; O, 16)
Click here to see answer by KMST(5328)

Question 625521: How many different ways can the letters M,A,T and H be ordered if no repetition is permitted?
Click here to see answer by jim_thompson5910(35256)

Question 625519: A truck headed east 2 hours before a bus headed east from the same location. The rate of the bus was 60 mph, and the rate of the truck was 40 mph. How long did it take the bus to get 20 miles ahead of the truck?
Click here to see answer by josmiceli(19441)

Question 625518: The sum of the digits of a two-digit counting number is 9. When the digits are reversed, the new number is 45 less than the original number. What is the original number?
Click here to see answer by lwsshak3(11628)

Question 625596: please help me Complete the following:
1. 5 10 30 120 _____
Thank You so much!

Click here to see answer by Edwin McCravy(20056)

Question 625807: A two-digit counting number has a value that is 1 greater than 8 times the sum of its digits. If 3 times the tens' digit is 11 greater than the units' digit, what is the number?
Click here to see answer by lwsshak3(11628)

Question 625805: seven-sixteenths of the assembled throng squatted in place. If 6399 did not squat in place, how many did squat in place?
Click here to see answer by josmiceli(19441)

Question 625808: There are 6 chairs in a row. There are 11 students. How many ways can these students sit in the 6 chairs?
Click here to see answer by stanbon(75887)

Question 625854: 1+1/4+1/9+1/16+........................=?
Click here to see answer by Edwin McCravy(20056)

Question 625883: Find y:
p/m=b/m^2(y/a+z)
Click here to see answer by Alan3354(69443)

Question 626123: 746392?
Click here to see answer by Alan3354(69443)

Question 626875: 1.1 Given 16(x-2)^3+8(x-2)^4+4(x-2)^5+...... As a geometric sequence and x is not equal to 2
1.1.1 Calculate the value of x for which sequence converges
1.1.2 Determine the sum to infinity of the series if x=2.5
Click here to see answer by reviewermath(1029)

Question 626886: Write the following series in sigma notation
12+7+2+.........up to 7 terms
Click here to see answer by richard1234(7193)

Question 626886: Write the following series in sigma notation
12+7+2+.........up to 7 terms
Click here to see answer by jim_thompson5910(35256)

Question 626916: Evaluate: the top sigma is 4, the bottom sigma is i=0 and the middle is [3*2^(i+1)-1].
Click here to see answer by solver91311(24713)

Question 626918: Consider the following sequence of numbers:
2;4;2;7;2;10;2;13;...
1.3.1 If the sequence behaves consistently, write down the 12th term of the above sequence?
1.3.2 Calculate the sum of the first 50 terms of the sequence.
Click here to see answer by psbhowmick(878)

Question 626885: Consider the following sequence of numbers:
2;4;2;7;2;10;2;13;...
a) Calculate the sum of the 50 terms of sequence.
Click here to see answer by psbhowmick(878)

Question 626915: A girl wants to buy her mother a birthday gift which is worth R900. She has only R400 and the birthday is in 10 days time. She decided to sell sweets to raise more money. On the first day she made a profit of 50 cents, on second day her profit was R1, on the third day her profit was R2, and so on until the 10th day.
1.2.1 Determine the total profit that the girl made.
1.2.2 Is she going to be able to afford the gift? Explain.
Click here to see answer by stanbon(75887)

Question 627027: find the general term an for the geometric sequence
a1 = -6
a2 = 30
Click here to see answer by jim_thompson5910(35256)

Question 627194: 87,102,105,111,114 . find the next number?
Click here to see answer by jim_thompson5910(35256)

Question 627931: show that the points (6,7)(2,3)(4,5) lie on a straight line
Click here to see answer by ewatrrr(24785)

Question 628105: Given the sequence 3,7,13,21,31,...,183,k,241,... find k
a.201
b.203
c.207
d.211
e.223
Click here to see answer by fcabanski(1391)

Question 628389: Evaluate the sum.
8
Σ (i - 7)
i=1
Click here to see answer by John10(297)

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