Question
Mathematics Question on Sets
If fourth term of an A.P. is zero, then t25t11 is, where tn denotes the nth term of AP.
A
(A) 2
B
(B) 3
C
(C) 4
D
(D) 5
Answer
(B) 3
Explanation
Solution
Explanation:
Let the first term of AP be 'a' and the common difference be 'd'.Given: Fourth term of an A.P. is zero.⇒a4=0nth term of the A.P. is given by an=a+(n−1)d⇒a+(4−1)×d=0⇒a+3 d=0∴a=−3 dTo Find: t25t11⇒t25t11=a+24 da+10 d⇒t25t11=−3d+24d−3d+10d⇒t25t11=21 d7 d⇒t25t11=3Hence, the correct option is (B).