Question

which term of the arithmetic progression 120,115 ,110,.......is zero​

Answer 1

Answer:

25th term of this AP will be zero

Step-by-step explanation:

aₙ = a₁ + (n-1)d

Here aₙ = 0

a₁ = 120

d = 115 - 120 = -5

So 0 = 120 + (n-1)*-5

(n-1)*5 = 120

n-1 = 120/5 = 24

n = 24 + 1 = 25

Answer 2

Answer:

1st term of an AP is (a) 120,

c. d(d) is 115-120=-5,

let the nth term of an AP be zero.

ATA

a+(n-1) d=nth term

or, 120+(n-1)(-5)=0

or, -5n+5=-120

or, -5n=-120-5

or, -5n=-125

or, n=-125/-5

or, n=25

since, 25th term of an AP be zero.