Choose the option that shall come in place of the ? in the following series : 25WV52, 23TS32, 21QP12, ?, 17KJ71

Question

FirstInTest · Accepted Answer

Correct answer: C. Let's break down the series into its components: first number, first letter, second letter, and last number.

1. First number series: 25, 23, 21, ?, 17
This is a decreasing series with a difference of -2: $25-2=23$, $23-2=21$, $21-2=19$, $19-2=17$. So the missing first number is 19.

2. First letter series: W, T, Q, ?, K
This is a decreasing series based on alphabetical position with a difference of -3: W (23) - 3 = T (20), T (20) - 3 = Q (17), Q (17) - 3 = N (14), N (14) - 3 = K (11). So the missing first letter is N.

3. Second letter series: V, S, P, ?, J
This is a decreasing series based on alphabetical position with a difference of -3: V (22) - 3 = S (19), S (19) - 3 = P (16), P (16) - 3 = M (13), M (13) - 3 = J (10). So the missing second letter is M.

4. Last number series: 52, 32, 12, ?, 71
This is a decreasing series with a difference of -20: $52-20=32$, $32-20=12$. The next term should be $12-20 = -8$. However, the next given term is 71. This suggests a different pattern or an error in the last number series. Let's re-examine the solution's explanation for the last number: "Pattern: -20 each $\rightarrow$ 52, 32, 12, (-20 $\rightarrow$ -8 $\rightarrow$ 92), 71". This implies that the pattern is not simply -20. It seems the solution implies that the number after 12 is -8, and then -8 becomes 92, and then 71. This is highly irregular. Let's assume there's a typo in the solution's explanation and the pattern for the last number is different or simpler. If we look at the options, the last number for the correct option is 91 or 92.
Let's re-evaluate the last number series: 52, 32, 12, ?, 71.
Differences: $32-52 = -20$, $12-32 = -20$. So the next term should be $12-20 = -8$. This is not a positive number as expected in the options.
Let's consider the possibility of a cyclic pattern or a different operation. If the last number is 92 (from option 3), then $12 \rightarrow 92$. This is $+80$. Then $92 \rightarrow 71$ is $-21$. This is not a consistent pattern.

Let's re-check the solution's last number explanation: "Pattern: -20 each $\rightarrow$ 52, 32, 12, (-20 $\rightarrow$ -8 $\rightarrow$ 92), 71". This is very confusing. It says "-20 each" but then shows -8 and 92. It's possible the last number is not a simple arithmetic progression.

Let's assume the solution's final answer is correct (19NM92) and work backward for the last number.
If the missing term is 19NM92, then the last number is 92.
Series: 52, 32, 12, 92, 71.
Differences: -20, -20, +80, -21. This is not a simple pattern.

However, if we consider the options, the only option that fits the first number and letters is 19NMxx. Option C is 19NM91. Option B is 19ON92 (wrong letters). Option A is 19MN91 (wrong letters). Option D is 19LK92 (wrong letters).

Let's assume the solution's explanation for the last number is flawed, but the first number and letters are correct. The options are:
1. 19MN91 (M is wrong)
2. 19ON92 (O is wrong)
3. 19NM91 (N, M are correct)
4. 19LK92 (L, K are wrong)

Wait, the first letter series is W, T, Q, ?, K. So the missing letter is N. The second letter series is V, S, P, ?, J. So the missing letter is M.
So the middle letters should be NM.

Let's re-check the options for the letters:
1. 19MN91 (MN - incorrect order)
2. 19ON92 (ON - incorrect letters)
3. 19NM91 (NM - correct letters in correct order)
4. 19LK92 (LK - incorrect letters)

So, based on the first number and the two letters, 19NM is the only possibility. Now we need to determine the last number, which is either 91 or 92.

Let's re-examine the last number series: 52, 32, 12, ?, 71.
If the pattern is related to the digits, or some other complex rule, it's not immediately obvious. However, if we assume the solution's final answer 19NM92 is correct, then the last number is 92. The provided option 3 is 19NM91. This is a discrepancy.

Given the solution states "Correct Answer: 3. 19NM92", and option 3 is "19NM91", there is a mismatch. I will use the solution's derived value for the last number (92) and the option that matches the first number and letters (19NM). Since none of the options perfectly match 19NM92, I will use 19NM91 and note the discrepancy. However, the provided solution explicitly states 19NM92. Let's assume the option text for 'C' should be '19NM92'.

Let's assume the last number pattern is: $X_n = X_{n-1} - 20$. So $12 - 20 = -8$. This doesn't fit the options.

Let's assume the solution's explanation for the last number is correct: "52, 32, 12, (-20 $\rightarrow$ -8 $\rightarrow$ 92), 71". This implies that after 12, the next number is -8, and then somehow it becomes 92. This is highly improbable for a standard series. It's more likely that the solution's explanation is trying to justify 92, or there's a typo in the question/options/solution.

Given the strong pattern for the first number and letters, I will prioritize those. The first number is 19, and the letters are NM. This leads to 19NMxx. Option C is 19NM91. If the solution says 19NM92, it implies a typo in the option text or the solution text.
I will use 19NM91 as per the option text, and note the confidence due to the last number ambiguity.

Final check of solution: "Missing term: 19NM92 Correct Answer: 3. 19NM92". This confirms the intended answer is 19NM92. I will use 19NM92 as the correct answer and assume option C should have been 19NM92.

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