Which term of 7 + 11 +15 + ………………. is 67? A) 20 B) 6 C)

1.	Which term of 7 + 11 +15 + ………………. is 67? A) 20 B) 6 C) 16 D) 10
Answer» Correct option is (C) 16 7, 11, 15, ......... will form an A.P. whose first term is a = 7 & common difference is 4. Let \(n^{th}\) term of A.P. will be 67. \(\therefore a_n=67\) \(\Rightarrow a+(n-1)d=67\) \(\Rightarrow7+(n-1)4=67\) \((\because\) a = 7 & d = 4) \(\Rightarrow4(n-1)=67-7=60\) \(\Rightarrow n-1=\frac{60}4=15\) \(\Rightarrow n=15+1=16\) Hence, \(16^{th}\) term of 7, 11, 15, ......... will be 67. Correct option is C) 16

Which term of 7 + 11 +15 + ………………. is 67? A) 20 B) 6 C) 16 D) 10

Answer»

Correct option is (C) 16

7, 11, 15, ......... will form an A.P. whose first term is a = 7 & common difference is 4.

Let \(n^{th}\) term of A.P. will be 67.

\(\therefore a_n=67\)

\(\Rightarrow a+(n-1)d=67\)

\(\Rightarrow7+(n-1)4=67\) \((\because\) a = 7 & d = 4)

\(\Rightarrow4(n-1)=67-7=60\)

\(\Rightarrow n-1=\frac{60}4=15\)

\(\Rightarrow n=15+1=16\)

Hence, \(16^{th}\) term of 7, 11, 15, ......... will be 67.

Correct option is C) 16