Question

how many terms are there in the A.P and n= number of terms of A.P.?

Answer 1

let the number of terms be n.

according to question given :-

tn = 100, a= 20 , d= 5

now ,

using formula

tn = a + ( n - 1 ) d


100 = 20 + ( n-1) d

100 = 20+ ( n- 1 ) 5

100 = 20 + 5n - 5

100 - 20 + 5 = 5n

80 +5 = 5n

$\frac{85}{5}$
n = 17

or , n - 1 = 16

be brainly

Answer 2

Hey the answer is 16

I. E n=16