The first term of an AP. is 5, the common difference is 3 and the last term is 80; find the number of terms.

Explanation

first term of this A.Pis `a_1` `=5`

common difference of an A.P is given by

`d=3`

ast term of the A.P is` a _n` `=80`

the nth term of an A.P is given by.

`a_n` =`a _1` `+(n−1)d`

`=>a_n`` =5+(n−1)(3)`

`=>a_n``​=5+3n−3`
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