Question

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

Answer 1

a=5
d=3
An=80
n=?
An=a+(n-1)d
80=5+(n-1)3
75=(n-1)3
25=n-1n=26

Answer 2

$\bold\red{Ur\:AnSwER }$
an=a+(n-1)d
Here, a=first term __n__ d=common difference

●80=5+(n-1)3
●80=5+3n-3
●80=2+3n
●80-2=3n
●78=3n
n=78/3
n=$\boxed {26}$

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