Math question. On facebook, there are 5 people within a group. If everybody invites 5 more people, how much people will be in that group the next day. If the new people all invite 5 more people, how many are in the next day? do it for the next ten days and show your work. Most clearest individual gets best answer!
2007-11-09 15:00:14 · 6 answers · asked by fungrl89 1 in Science & Mathematics ➔ Mathematics
this isnt a homework problem, its a curiosity problem, and the reason my grammer is off is because english is not my first language, so mike, you're insulting comment is uncalled for. get a life. seriously.
2007-11-11 05:44:01 · update #1
If I follow correctly, only the new people from the previous day invite 5 new members
day0: 5 = 5 <-- initially 5 people
day1: 5+25 = 30 <-- original day0 people each invite 5
day2: 5+25+125 = 155 <-- day1 new people each invite 5
day3: 5+25+125+625 = 780 <-- day2 new people each invite 5 and so on...
day4: 5+25+125+625+3125 = 3905
day5: 5+25+125+625+3125+15625 = 19530
day6: 5+25+125+625+3125+15625+78125 = 97655
day7: 5+25+125+625+3125+ 15625+78125+390625 = 488280
day8: 5+25+125+625+3125+15625+ +8125+390625+1953125 = 2441405
day9: 5+25+125+625+3125+15625+78125 +1953125+9765625 = 12207030
day10: 5+25+125+625+3125+15625+78125 +1953125+9765625+48828125 = 61035155
and so on... which yields the following sequence
5, 30, 155, 780, 3905, 19530, 97655, 488280, 2441405, 12207030, 61035155
It can be shown (some how, I'm sure) that
An = (5^(n+2) -5) /4
[adapted from below link to fit my subscripting]
initally:5
day 1:30
day 2:155
day 3:780
day 4:3905
day 5:19530
day 6:97655
day 7:488280
day 8:2441405
day 9:12207030
day 10:61035155
day 11:305175780
day 12:1525878905
2007-11-09 15:17:03 · answer #1 · answered by radne0 5 · 0⤊ 0⤋
The first 5 people invite 5 people so 5*5 is 25. So the 5 people and the 25 new people make 30 group members. When the 25 new people invite 5 more people each you take 25*5 and get 125. Add 125+25+5 to get 155people. Keep doing this for the next 10 days.
2007-11-09 23:09:08 · answer #2 · answered by Breann O 1 · 0⤊ 0⤋
first day 5
next day those 5 + the 25 they invite = 30
next those 30 , 25 of whom are new and the 125 the newbies add = 155 which is 30X5+5
next those 155 plus the 625 the newbies add = 780 which is 155X5+5
so keep multiplying by 5 and adding 5 to get the next number in the sequence
2007-11-09 23:07:58 · answer #3 · answered by hayharbr 7 · 0⤊ 0⤋
It seems to be an like a compound interest growth problem.
Day 1 Day 2 Day 3 day 4
5 5+(5^2)=30 30+5(30)=180 180+5(180)=1080
day 5
1080+5(1080)=1080+5400=6480 and so on, and so on
2007-11-09 23:16:13 · answer #4 · answered by Will 4 · 0⤊ 0⤋
Day 1 = 5 people
Day 2 = 5*5 people = 5^2 = 25
Day 3 = 5*5*5 people = 5^3 = 125
...
...
Day 10 = 5*5*5*5*5*5*5*5*5*5 = 9765625
2007-11-09 23:07:05 · answer #5 · answered by Jeƒƒ Lebowski 6 · 0⤊ 0⤋
2,980,232,239,000,000,000 People!! Hope its right. LOL!
2007-11-09 23:11:35 · answer #6 · answered by Jsly 2 · 0⤊ 0⤋