SOLUTION: Please help me figure out this word problem. Considering yourself, your parents, your grandparents, and so on, back to your grandparents with the workd "great" used in front 40 tim

Algebra.Com
Question 65739: Please help me figure out this word problem. Considering yourself, your parents, your grandparents, and so on, back to your grandparents with the workd "great" used in front 40 times. What is the total number of people that you are considering. Thanks for your help.
Found 2 solutions by ntnk, stanbon:
Answer by ntnk(54)   (Show Source): You can put this solution on YOUR website!
Each level is 2^x (because each person has two parents and so forth.)
Therefore,
YOU are 2^0 = 1 (person);
PARENTS are 2^1= 2 (people);
GRANDPARENTS are 2^2= 4 (people);
GREAT GRANDPARENTS are 2^3=8;
GREAT GREAT GRANDPARENTS are 2^4=16;
GREAT GREAT GREAT GRANDPARENTS are 2^5=32;
and so forth.
But notice that three "greats" implies 2^5.
This means that x "greats" implies x+2. Therefore, 40 "greats" implies 2^42, which is the total number of people that you are considering.
Also, the question is a bit unclear as to if you want to know the total number of people including yourself and parents, and grandparents, and so forth until great*40 grandparents, so if you include ALL of those people, then it will be 2^42+2^41+2^40+...+2^20+2^19+...+2^3+2^2+2^1+2^0 and so forth.
and so forth
ntnk

Answer by stanbon(75887)   (Show Source): You can put this solution on YOUR website!
Parents=2
Grand parents=4=2^2
"Great" starts with 2^3 people
Each generation before that multiplies by 2
The last generation you want has 2^3*2^39=2^42
which is a very large number.
Comment: I can't tell if you are starting the count with yourself:
if you are the total number is:
1+2+2^2+2^3+...+2^42
Using the sum formula with r=2 and n=41 the sum is:
S(41)=1[2^(42)-1]/[2-1]
=2^42-1
=4.398046511x10^12
Cheers,
stan H.

RELATED QUESTIONS

as we know we have parents grandparents great grandparents and soon. what's the total... (answered by ikleyn)
I have been trying to figure out this problem for an hour now I cannot get the answer the (answered by drk)
I have been trying to figure out this problem for an hour now I cannot get the answer the (answered by Theo)
Please help me out to find an answer to this question. A shirt cost 97cedis but you... (answered by Theo)
Hello Tutors, I need your help here Please. I can not for the life of me figure out how... (answered by bucky)
I can not figure out the solution to this problem. can you please help me. I need to... (answered by Theo)
I am stumped! I have been at this math problem for what seems like hours. I would really... (answered by gonzo,Mathtut)
Good Evening, I'm having a hard time catching on to linear equations and graphing them. (answered by mananth)
In solving the equation (x + 4)(x – 4) = 9, Eric stated that the solution would be x + 4 (answered by ewatrrr)