Question

which term of AP : 3,8,13,18,......,is 78?
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Answer 1

Answer:

The given sequence is 3, 8, 13, 18, ....78.

'a' = 3, 'd' = 5, last term = 78, 'n' = ?

t

n

=a+(n−1)d

⟹78=3+(n−1)5

⟹78=3+5n−5

⟹78=5n−2

⟹5n=80orn=16.

Answer 2

Yes,

The given sequence is 3, 8, 13, 18, ....78.

'a' = 3, 'd' = 5, last term = 78, 'n' = ?

tn =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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