Question

Which term of the A.P. : 120,116,112,….. is its last positive term.

Answer 1

Answer:

hope this helps u

32nd term....

a=120

d=-4

Let a(n)=0

so,

a(n)=a+d(n-1)

0=120-4(n-1)

-120=-4(n-1)

30=n-1

31=n

checking...

a(n)=a+d(n-1)

=120-4(32-1)

=120-4(31)

=120-124

= -4

31st term gave me zero so 32nd term will be -ve