SOLUTION: You have a series of numbers, where the sum of the previous two numbers (except for the first two) adds up to the next one. (Like the Fibanachi sequence), the first number is 1 and

Algebra.Com
Question 310517: You have a series of numbers, where the sum of the previous two numbers (except for the first two) adds up to the next one. (Like the Fibanachi sequence), the first number is 1 and the 10th number is 111. What is the second number?
Answer by Edwin McCravy(20056)   (Show Source): You can put this solution on YOUR website!

Let the 2nd number be x.  Then the numbers are

#1.  1
#2.  x
#3.  1+x
#4.  x+(1+x)=x+1+x=1+2x
#5.  (1+x)+(1+2x)=1+x+1+2x=2+3x
#6.  (1+2x)+(2+3x)=1+2x+2+3x=3+5x
#7.  (2+3x)+(3+5x)=2+3x+3+5x=5+8x
#8.  (3+5x)+(5+8x)=3+5x+5+8x=8+13x
#9.  (5+8x)+(8+13x)=5+8x+8+13x=13+21x  
#10. (8+13x)+(13+21x)=8+13x+13+21x=21+34x

Since term #10 is 111:






Checking, the numbers go

,,,,,,,,,

Edwin


RELATED QUESTIONS

How do you set this word problem up? Two numbers have a sum of 106. One number is 10... (answered by Alan3354)
Hi I have a couple of problems that I would like to know how to solve. The involve the... (answered by checkley71)
Two numbers have a sum of 39. Their difference is 11. What are the two numbers. Please... (answered by askmemath)
In the sequence 1,4,5,6,7,8,10,16,18,... each number after the first two is the next... (answered by greenestamps)
In the sequence 1,4,5,6,7,8,10,16,18,... each number after the first two is the next... (answered by greenestamps)
In the sequence 1,4,5,6,7,8,10,16,18,... each number after the first two is the next... (answered by greenestamps)
the smaller of two numbers is 23 less than three times the smaller.the number adds up to... (answered by fractalier)
A box contains five slips of paper. Each slip has one of the numbers 4,6,7,8,or 9 written (answered by ewatrrr)
the sum of two numbers is 47. Find the two numbers if one is two more than four times... (answered by rfer)