Sum 7+10+13+15+...+97+100 = ?

Arithmetic and Geometric progressions.

Sum 7+10+13+15+...+97+100 = ?

Postby dduclam » Tue Mar 25, 2008 2:37 am

Find the sum:

[tex]P= 7+10+13+15+...+97+100[/tex]
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Postby Math Tutor » Tue Mar 25, 2008 2:53 am

Are you shure that the problem is not
P = 7 + 10 + 13 + 16 + ... + 97 + 100 ?

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edit

Postby dduclam » Tue Mar 25, 2008 3:33 am

teacher wrote:Are you shure that the problem is not
P = 7 + 10 + 13 + 16 + ... + 97 + 100 ?


Yes,thank you,teacher :) P = 7 + 10 + 13 + 16 + ... + 97 + 100

math is my life
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Postby icb » Wed May 14, 2008 8:10 am

This is an arithmetical progression.

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Postby prasanna_chandran » Thu Nov 05, 2009 9:27 am

1st term is 7, last term is 100, d- common difference is 3.

So we need only n, to find out the Sn=1/2 (a 1st term + a nth term) * n

=1/2*(7+100)*n

100=(7+31*3) , where a=7, 3=d, and a(nth) term = 100, and 31 is the (n-1)th term.

total terms= 32.

Sn= 1/2(7+100)*32= 16*107=1712.

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Re: Sum 7+10+13+15+...+97+100 = ?

Postby burgess » Mon Jul 14, 2014 6:25 am

dduclam wrote:Find the sum:

[tex]P= 7+10+13+16+...+97+100[/tex]


It is an arithmetic progression
a=7, n,d=3
first we will find out number of terms
7 + (n-1)*3 =100
n-1=93/3=31 => n=32

Sum = n/2 *[first term + last term] = 16*107
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Re: Sum 7+10+13+15+...+97+100 = ?

Postby Alicelewis11 » Sun Jul 27, 2014 6:53 am

Yes, we can use this formula to sum all integers (N(N + 1))/2...............

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Re: Sum 7+10+13+15+...+97+100 = ?

Postby burgess » Wed Aug 27, 2014 6:25 am

Use the arithmetic series formulas

dduclam wrote:Find the sum:

[tex]P= 7+10+13+15+...+97+100[/tex]

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Re: Sum 7+10+13+15+...+97+100 = ?

Postby zaiveca » Fri Oct 03, 2014 6:26 am

This is really great!

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Re: Sum 7+10+13+15+...+97+100 = ?

Postby leesajohnson » Mon Jan 18, 2016 5:16 am

Sum 7+10+13+15+...+97+100 = ?

The answer for this question is 1712.

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