Which term of the AP: 3, 8, 13, 18 … is 78?

1.	Which term of the AP: 3, 8, 13, 18 … is 78?
Answer» A=3 d=5 Tn=78Formula :- a + (n-1)dPutting value,3 + (n-1)5 = 78(n-1)5 = 78-3(n-1)*5 = 75(n-1) = 75/5n-1) = 15n = 15+1 = n = 16 16 The given sequence is 3, 8, 13, 18, ....78.\'a\' = 3, \'d\' = 5, last term = 78, \'n\' = ?tn\u200b=a+(n−1)d⟹78=3+(n−1)5⟹78=3+5n−5⟹78=5n−2⟹5n=80orn=16.The 16th term is 78.

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