Question

If the sum of first n terms of an arithmetic progression 2, 5, 8 ........ is equal to the sum
of first n terms of another arithmetic progression 57, 59, 61 ......... Then find the value
of n.
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Answer 1

Step-by-step explanation:

This is my answer i hope this helps mark brainliest

Answer 2

The value of n is 111

Step-by-step explanation:

Given two A.P.

In given A.P.  2, 5, 8 ,.....

a= 2 and d= 5-2=3 where a is the first term and d is the common difference

as we know the sum of n terms of an A.P. is given by

$S_n= \dfrac{n}{2} (2a+(n-1)d)$

so

$S_n=\dfrac{n}{2} (2\times 2_(n-1)\times 3)$

similarly inn given A.P. 57, 59, 61, .... a= 57 and d= 59-57= 2

$s_n=\dfrac{n}{2} (2\times 57+(n-1)2)$

The sum of n terms of these two A.P is equal

$\dfrac{n}{2} (2 \times 2+(n-1)3)=\dfrac{n}{2} (2 \times 57+(n-1)2)\\\\ 4+3n-3=114+2n-2\\\\1+3n=112+2n\\\\3n-2n=112-1\\\\n=111$

Hence the value of n= 111

#Learn more

For what value of n are the nth term of the AP 15,12,9 .......and -15, - 13,-11..... equal

brainly.in/question/5112815