Input-Output Questions for SBI PO

What Is Input-Output

A machine takes an input line of words and/or numbers and rearranges them step by step. Each step follows a fixed hidden rule. Your job is to figure out that rule by comparing Step 1, Step 2 etc., then answer questions like: what does Step 3 look like, or in which step does a given arrangement appear. Think of it like a washing machine: every cycle does the same thing to the clothes, just repeated.

• Input is given. Steps are the machine output at each stage.
• The rule is CONSISTENT across every step — same action repeats.
• Questions ask: find a particular step, find the input from a step, or count total steps.
• SBI PO often gives only some steps (not all) and asks you to reconstruct.
• The final step is when no further rearrangement is needed (fully sorted or a pattern completes).

Types of Rules You Will See

There are 5 common rule patterns. SBI PO 2023-24 favoured the Dual Operation type where BOTH ends of the line get rearranged in the same step. Always check both ends before assuming a rule.

• Type 1 - Alphabetical Sorting: Words arranged A to Z from left or right, one word per step.
• Type 2 - Numerical Sorting: Numbers arranged ascending or descending, one number per step.
• Type 3 - Alternating Ends: One element goes to the left end, next goes to the right end, alternating each step.
• Type 4 - Dual Operation (SBI Favourite): In one step, one word moves to left AND one number moves to right (or vice versa).
• Type 5 - Value-Based: Numbers rearranged by sum of digits, word length, or alphabetical rank of first letter.

Step-by-Step Rule Detection Method

You have 90-120 seconds to crack the rule. Use this 3-step method every time. First, compare Input vs Step 1 — note exactly which elements moved and where they went. Second, compare Step 1 vs Step 2 — confirm the SAME action happened again. Third, verify once with Step 2 vs Step 3 if available. Never assume after just one comparison.

• Highlight the element that appears newly at the leftmost position in each step.
• Check if a corresponding element appeared at the rightmost position too (dual clue).
• Count elements: if 8 elements, expect around 4 steps for dual operation type.
• If rule seems alphabetical, check if it is by word or by number separately.
• Write the rule in a short note: e.g. Smallest number to left, largest word (by length) to right each step.

Calculating Any Step Without Writing All Steps

In Dual Operation type, each step places 2 elements in their final position (one left, one right). So after N steps, the first N elements from left and last N elements from right are fixed. This lets you jump directly to any step without drawing every step. This saves 1-2 minutes in the exam.

• For Dual Operation: After Step N, N elements are locked on the left, N on the right.
• For Single Operation (one element per step): After Step N, N elements are locked on one side.
• To find Step 3 directly: identify the 3 elements that would be locked left and 3 locked right, then arrange the remaining middle elements as they were in the original order.
• Total steps for Dual Op with 8 elements = 4 steps (8 divided by 2).
• Total steps for Single Op with 8 elements = 8 steps.

Special SBI PO Variant: Coded Input-Output

SBI PO Mains 2023 introduced a coded variant where the machine assigns a code to each step output (e.g. numbers shift by +2, letters shift by one position in alphabet). You must first decode the logic, then answer which step gives a particular code. Treat it as two puzzles: first crack the arrangement rule, then crack the coding rule.

• Coded variant appears in Mains, not usually Prelims.
• Compare numeric changes between steps to find the shift pattern.
• Check if words swap letters or reverse order as part of coding.
• Solve arrangement rule first, coding rule second — do not mix the two.
• These sets carry high marks so spend up to 3 minutes on rule detection here.

• Assuming the rule after comparing only Input and Step 1 — always verify with at least two consecutive steps before committing.
• Missing dual operation — students check only the left end and miss that the right end is also changing simultaneously, leading to a wrong rule.
• Re-drawing every step when a direct jump calculation is possible — this wastes 2-3 minutes which is fatal in SBI PO speed conditions.
• Confusing alphabetical order of words with ascending order of numbers in the same set — keep words and numbers tracked separately in your rough work.
• In the final step identification, stopping one step too early because the line looks 'almost sorted' — always confirm no further change is possible.

• RULE BEFORE YOU DROOL: Never start answering before you confirm the rule with 2 step comparisons. One look is never enough.
• LRLR Trick for Dual Op: Left Right Left Right — alternate placing elements. If step 1 puts something on Left, it also puts something on Right. Count pairs not singles.
• FREEZE THE ENDS: After each step in dual op, the outermost elements are frozen like ice — only the middle unfrozen elements keep moving.
• The Washing Machine Analogy: The rule is the washing cycle. Same cycle repeats every step. Find the cycle setting, then predict what the clothes look like after 3 or 4 washes.

• SBI PO Prelims typically gives 1 set of 5 questions on Input-Output. It is usually a Dual Operation type with 8 elements (4 words + 4 numbers). Expect 6-7 minutes for the full set — aim to crack the rule in under 90 seconds.
• SBI PO Mains may introduce coded or multi-condition variants where two rules operate simultaneously. These appear in the harder puzzle cluster. Attempt only after completing simpler sets.
• A common SBI PO pattern: input has 3-digit numbers mixed with words. Rule is ascending numbers go left, words in reverse alphabetical order go right. Practice this exact pattern.
• If you cannot crack the rule in 2 minutes, skip the set and return. Do not sit on it — other sets in Reasoning are more time-predictable.
• In the answer options, two choices often differ only by the position of middle elements. This means your rule detection must be precise — even one wrong element position will trick you into a wrong answer.