Which term of the A. P. 15, 20, 25, ... is 115?

1.	Which term of the A. P. 15, 20, 25, ... is 115?
Answer» Given,a=25d=20−25=−5Tn\u200b<0a+(n−1)d<025+(n−1)(−5)<025<5(n−1)5<(n−1)n>6⇒n=77th term is negative.a7\u200b=25+(7−1)(−5)=25−5×6=−5

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