Question

In an AP, The ratio of$7^{th}$term to$3^{th}$term is in ratio$2:1$. Find the ratio of${11}^{th}$term to$8^{th}$term.

• A. 3: 4
• B. 4: 3
• C. 2: 5
• D. 5: 2
• E. 2: 1

Answer 1

The correct option is B 4: 3

Solution: Option (b)

Let the first term be a, common difference be d.

$t_7=a+6d,t_3=a+2d,t_7=2t_3\Rightarrow a+6d=2(a+2d)\Rightarrow a=2d.$

$t_{11}=a+10d=2d+10=12d$

$t_8=a+7d=2d+7d=9d$

So, required ratio$=12d:9d=4:3$