MCQ 11 Mark
Assertion $(A):$ Three consecutive terms $2 k+1,3 k+3$ and $5 k-1$ form an $AP$ than $k$ is equal to $6 .$
Reason $(R):$ In an $AP\ a , a + d , a +2 d, \ldots$ the sum to $n$ terms of the $AP$ be $S _{ n }=\frac{n}{2}(2 a+(n-1) d)$
Reason $(R):$ In an $AP\ a , a + d , a +2 d, \ldots$ the sum to $n$ terms of the $AP$ be $S _{ n }=\frac{n}{2}(2 a+(n-1) d)$
- ABoth $A$ and $R$ are true and $R$ is the correct explanation of $A.$
- ✓Both $A$ and $R$ are true but $R$ is not the correct explanation of $A.$
- C$A$ is true but $R$ is false.
- D$A$ is false but $R$ is true.
Answer
View full question & answer→Correct option: B.
Both $A$ and $R$ are true but $R$ is not the correct explanation of $A.$
For $2 k+1,3 k+3$ and $5 k-1$ to form an $AP$
$(3 k+3)-(2 k+1)=(5 k-1)-(3 k+3)$
$k+2=2 k-4$
$2+4=2 k-k=k$
$k=6$
So, both assertion and reason are correct but reason does not explain assertion.
$(3 k+3)-(2 k+1)=(5 k-1)-(3 k+3)$
$k+2=2 k-4$
$2+4=2 k-k=k$
$k=6$
So, both assertion and reason are correct but reason does not explain assertion.
