Answer:
Given, A.P. is 27, 24, 21,... We have, \[a=27,\text{ }d=24-27=21-24=-3\] Now, \[{{S}_{n}}=0\] Therefore, \[{{S}_{n}}=\frac{n}{2}[2a+(n-1)d]=0\] \[\Rightarrow \,\frac{n}{2}[2(27)+(n-1)(-3)]=0\] \[\Rightarrow \,54-3n+3=0\] \[\Rightarrow \,57-3n=0\] \[\Rightarrow \,3n=57\] \[\therefore n=19\] Hence, the no. of terms are 19
You need to login to perform this action.
You will be redirected in
3 sec