numbers in progression...

azajewel

New member
Joined
Aug 30, 2010
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11
What is the next number in this progression? 5, 25, 125, 625...

750
1250
3125
390,625

I can't figure out the sequence here, any help is appreciated.
 
azajewel said:
What is the next number in this progression? 5, 25, 125, 625...

750
1250
3125
390,625

I can't figure out the sequence here, any help is appreciated.

You might want to look at how the GIVEN numbers are related.

Do you see that the first number (5) multiplied by 5, gives the second number?

And that the second number (25) multiplied by 5, gives the third number?

Now....you might want to take this train of thought a bit further.....
 
\(\displaystyle a_n \ = \ a_1r^{n-1}, \ a_n \ = \ last \ term, \ a_1 \ = \ first \ term, \ n \ = \ number \ of \ terms,\)

\(\displaystyle and \ r \ = \ common \ ratio. \ Can \ you \ take \ it \ from \ here?\)

\(\displaystyle Or \ 5^1,5^2,5^3,5^4,5^?\)
 
That is perfectly right. I would also suggest checking out their common denominator next time so you will know the next in line.
 
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