Please solve the 20th sum
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For 1st AP
a=8
d=20
Sn1=n/2 {2a+(n-1)d}
=n/2{2×8+(n-1)20
=n/2{16+20n-20
=n/2{20n-4} ........eq 1
For 2nd AP
a=-30
d=8
Sn2=n/2{2a+(n-1)d}
=n/2{-60+8n-8}
=n/2{8n-68} ..........eq 2
given
Sn1=Sn2
n/2{20n-4}=n/2{8n-68}
20n-4=8n-68
20n-8n=68+4
12n=72
n=6
hope it helps u
a=8
d=20
Sn1=n/2 {2a+(n-1)d}
=n/2{2×8+(n-1)20
=n/2{16+20n-20
=n/2{20n-4} ........eq 1
For 2nd AP
a=-30
d=8
Sn2=n/2{2a+(n-1)d}
=n/2{-60+8n-8}
=n/2{8n-68} ..........eq 2
given
Sn1=Sn2
n/2{20n-4}=n/2{8n-68}
20n-4=8n-68
20n-8n=68+4
12n=72
n=6
hope it helps u
isha7928:
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Answered by
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Answer:
Step-by-step explanation:
Sn=S2n........... (given)
By the solving sn term.....
We get....
n/2(20n-4)....... equation no 1
By the solving s2n term.....
We get....
n/2(8n-68)....... equation no 2
n/2(20n-4) =n/2(8n-68)...... (according the given condition)
Then we get......
20n-4=8n-68
20n-8n=-68+4
-12n=-64
Sorry..... I am writing and unwantedly it send.....
n=64/12
n=5.333333333
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