an important question from the book -ML aggarwal( avichal publication)class 10th , chapter9, arithmetic progression …….. This type of question has been asked in paper. so please solve it in detail. we have been asked
Which term of the AP 3, 8, 13, 18 is 78?
Clasa 10, ML Publication, Arithmetic Progression Chapter 3 question no. 6(i)
Rajan@2021Guru
Which term of the AP 3, 8, 13, 18 is 78?
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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=80
or n=16.
The 16th term is 78.