A) \[24\]
B) \[120\]
C) \[0\]
D) None of these
Correct Answer: C
Solution :
11th term of an \[AP=a+(11-1)\,d=a+10d\] 21st term of an \[AP=a+20d\] and 25th term of an \[AP=a+24d\] According to the given condition, \[2(a+10d)=7(a+20d)\] \[\Rightarrow \] \[2a+20d=7a+140d\] \[\Rightarrow \] \[-5a=120d\] \[\Rightarrow \] \[a=-\frac{120}{5}\,d=-24d\] \[\therefore \] 25th term \[=-24d+24d=0\]You need to login to perform this action.
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