We are given the following algebraic equations:
The objective is to determine the value of the product $PQR$.
From Equation 1, we can isolate $P$:
$P = 1 - \frac{1}{Q}$
Combine the terms on the right side:
$P = \frac{Q - 1}{Q}$
From Equation 2, we can isolate $\frac{1}{R}$:
$\frac{1}{R} = 1 - Q$
Assuming $Q \neq 1$ (which must be true, otherwise $1/R = 0$, which is impossible), we find $R$:
$R = \frac{1}{1 - Q}$
Substitute the derived expressions for $P$ and $R$ into the product $PQR$:
$PQR = \left(\frac{Q - 1}{Q}\right) \times Q \times \left(\frac{1}{1 - Q}\right)$
Cancel the variable $Q$ present in the numerator and denominator:
$PQR = (Q - 1) \times \frac{1}{1 - Q}$
Factor out $-1$ from $(Q - 1)$:
$PQR = -(1 - Q) \times \frac{1}{1 - Q}$
Cancel the $(1 - Q)$ terms:
$PQR = -1 \times 1$
$PQR = -1$
The value of $PQR$ calculated from the given equations is -1.
In an examination, a student scores 4 marks for every correct answer and loses 1 mark for every wrong answer. If she/he attempts all 60 questions and secures 130 marks, the number of questions she/he attempts wrongly, are?
Match List-I with List-II
| List-1 | List-II |
| (A) If $\begin{bmatrix}\lambda-1 & 0 \\ 0 & \lambda-1 \end{bmatrix} $, then $\lambda$ is | (I) 0 |
| (B) If A=$ \begin{bmatrix}1 & 2 \\2 & 4 \end{bmatrix} $, then $\Delta$ is | (II) 1 |
| (C) If A = $ \begin{bmatrix}1 & 0 \\0 & \frac{1}{2} \end{bmatrix} $, then $|A^{-1}|$ is | (III) -2 |
| (D) If $ \begin{bmatrix}a+1 & 1 \\1 & 2 \end{bmatrix} = \begin{bmatrix}-1 & 1 \\1 & 2 \end{bmatrix} $, then a is | (IV) 2 |
Choose the correct answer from the options given below: