Find the sum of the first 19 terms of an ap whoses 8th term is 41 and 13term is 61
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Answer:
Step-by-step explanation:
a+7d=41
a+12d=61
After solving these eq.
5d=20
d=4
Put in any eq.
a=13
Then acc. To formula
19/2{2*13+(19-1)4}
19/2{26+72}
19/2(98)
19(49)
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