Find the middle term (s) in the A.P. 20,16,12,.........-176.

20,16,12,.......,-176 is in AP.

here, a=20     d=16-20=-4       an=-176

a+(n-1)d=-176

20+(n-1)(-4)=-176

(n-1)(-4)=-196

(n-1)=-196/-4=49

n=49+1=50

the middle term  between 1& 50 r 25th term &26th term 

a25=20+24*(-4)=20-96=-76

a26=20+25*(-4)=20-100=-80

the middle term of the given AP is -76 & -80...........

I HOPE THIS WILL HELP U.......