If 3+5+7+.....to n terms upon 5+8+11+....to 10 terms= 7 then the value of n is??
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3+5+7+...+n/5+8+.....upto 10 terms
solve denominator first
S10=10\2[2×5+(10-1)3]
S10=185
now 3+5+7......n\185=7
3+5+7....n=185×7
3+5+7+....n=1295
Sn=n/2[2a+(n-1)d]
1295×2=6n+2n*2-2n
2590=4n+2n*2
4n+2n*2-2590=0
by quadratic formula n is either 35 or 37
solve denominator first
S10=10\2[2×5+(10-1)3]
S10=185
now 3+5+7......n\185=7
3+5+7....n=185×7
3+5+7+....n=1295
Sn=n/2[2a+(n-1)d]
1295×2=6n+2n*2-2n
2590=4n+2n*2
4n+2n*2-2590=0
by quadratic formula n is either 35 or 37
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