1.

12th term of the sequence 5, 14, 23, …………. isA) 900 B) 104 C) 239 D) 100

Answer»

Correct option is (B) 104

Given sequence is 5, 14, 23, ......

\(\therefore a_1=5,a_2=14,a_3=23\)

Now \(a_2-a_1=14-5=9,\)

\(a_3-a_2=23-5=9\)

\(\because\) \(a_2-a_1\) \(=a_3-a_2\)

\(\therefore\) Given sequence is an arithmetic progression whose first term is 5 & common difference is 9.

\(\because\) \(a_{12}=a+11d\)        \((\because a_n=a+(n-1)d)\)

\(=5+11\times9\)             \((\because a=a_1=5\;\&\;d=a_2-a_1=9)\)

\(=5+99=104\)

Correct option is B) 104



Discussion

No Comment Found