🧩 DILR

Puzzle Test

Mixed grid puzzles linking people, attributes, and positions.

12%

of DILR

Why This Topic Matters

Total PYQs📊

of 1002 · 2021–2025

Years featured📅

5/5

of recent CAT years

% of DILR📈

~12%

of section questions

Est. hours⏱️

~8h

to master

~6/20

2021

~2/20

2022

~2/20

2023

~2/22

2024

~2/22

2025

Scheduling & Puzzle Sets

Assign events to slots in time — days, time-slots, rounds — under precedence ("A before B"), adjacency ("C right after D"), and capacity rules. A grid of slots plus disciplined elimination cracks them.

Where scheduling showed up	2021	2022	2023	2024	2025	Avg/slot
Pure scheduling sets	3.3	–	–	–	1.7	1.0
Scheduling inside LR sets	2.0	–	–	1.7	–	0.7
Scheduling inside DI sets	–	–	1.7	–	–	0.3
Routes-with-timetable sets	–	1.7	–	–	–	0.3

🎯PYQ Evidence

Scheduling never skips a year — it just changes section labels. 2021 ran pure scheduling sets, 2022 hid it in a routes set, 2023 served it as DI-scheduling, 2024 as an LR set, 2025 as pure scheduling again (5 questions). That's on average about 2–3 questions per slot of the same core skill: timeline + precedence + capacity. This is among the highest-yield DILR skills to master.

Method

Lay out the timeline as labelled slots.
Place fixed events ("E is on Monday") immediately.
Convert precedence to bounds: "A two days before B" both orders them and limits their possible slots.
Adjacency = a block: "C immediately after D" travels as one unit.
Eliminate until each slot is forced.

A worked example

✏️Worked Example

Five lectures — Physics, Chemistry, Biology, Maths, CS — are scheduled Mon–Fri, one per day. (1) Maths is on Wednesday. (2) Biology is on Friday. (3) CS is immediately after Physics. (4) Physics is before Chemistry.

Fixed: Wed = Maths, Fri = Biology. Free days: Mon, Tue, Thu.
The Physics→CS block needs two consecutive free days. Among Mon, Tue, Thu, only Mon–Tue are consecutive (Wed sits between Tue and Thu). So Physics = Mon, CS = Tue.
Chemistry takes the last free day, Thu — and indeed Physics (Mon) is before Chemistry (Thu). ✓

The whole timetable was forced — no guessing.

🎯PYQ Evidence

The real CAT version adds one twist: capacity. A typical recent scheduling set (e.g. the 16-classes/7-teachers/4-days pattern) fixes how many events each day holds ("5 classes on Monday and Sunday, 3 on Wednesday and Friday") and how many each person may take ("each teacher 1–3 classes, never two on the same day"). Those capacity numbers are your strongest clues — total them first ( $5+5+3+3=16$ ✓) and squeeze group counts against them before placing anything.

🎯PYQ Evidence

Crack a puzzle set by fixing the one thing the constraints force, then letting the grid fall out. : the span is the anchor — Acharya Raghunath is barred except in two-year windows, so his span must be 2, leaving spans 3 and 4 for the others; combined with the 2013 starts and the "Gurubhai exactly twice" counts, the entire year-by-year timeline is forced, after which counting (only two students training in 2017, 2018, 2023, 2024) is direct. : here the "grid" is a rules engine — translate level (1 or 2) and campaign type into the turnout formula 20 x (sum of levels)%, then apply the fixed attack transfers, and test the few combinations to find extremes. Read the constraints as a machine that has one setting, not a search.

Common traps

⚠️CAT Trap

Precedence ≠ adjacency. "Before" allows gaps; "immediately before" does not. And when a fixed event sits mid-week, count consecutive free slots around it carefully — Tue and Thu are not consecutive when Wed is taken. Most scheduling-set errors are one of these two misreads.

Missing a capacity rule ("at most two per slot") that quietly kills a branch.

Checklist

Draw the timeline; drop in fixed events
Total the capacities and check them against the event count
Turn "before/after" into bounds, adjacency into blocks
Find the only consecutive gap for adjacency pairs
Verify every precedence clue in the final grid

Sample Questions

8 practice questions

Hard

Six people A,B,C,D,E,F take a driving test on different days Mon-Sat. B takes test on Thursday. A takes test 2 days before B. D takes test the day after C. E takes test on Monday. Which of the following is true? (a) F takes test on Fri (b) C takes test on Tue (c) F takes test on Sat (d) A takes test on Tue

Hard

Seven people M,N,O,P,Q,R,S meet Thu-Wed (one per day). Constraints: 3 people between R and N; 1 between O and N; 1 between O and R (not after O); 3 between M and O; M not after Saturday; P just after M; 1 between P and S. On which day does N attend?

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CAT PYQ Spotlight

Actual CAT questions on this topic

Context

Ananya Raga, Bhaskar Tala, Charu Veena, and Devendra Sur are four musicians. Each of them started and completed their training as students under each of three Gurus — Pandit Meghnath, Ustad Samiran, and Acharya Raghunath between 2013 and 2024, including both the years. Each Guru trains any student for consecutive years only, for a span of 2, 3, or 4 years, with each Guru having a different span. During some of these years, a student may not have trained under these Gurus; however, they never trained under multiple Gurus in the same year. In none of these years, any of these Gurus trained more than two of these students at the same time. When two students train under the same Guru at the same time, they are referred to as Gurubhai, irrespective of their gender.

The following additional facts are known:

1. Ustad Samiran never trained more than one of these students in the same year.

2. Acharya Raghunath did not train any of these students during 2015-2018, as well as during 2021-24.

3. Ananya and Devendra were never Gurubhai; neither were Bhaskar and Charu. All other pairs of musicians were Gurubhai for exactly 2 years.

4. In 2013, Ananya and Bhaskar started their trainings under Pandit Meghnath and under Ustad Samiran, respectively.

CAT 2025 · Slot 2

Hard

In which of the following years were Ananya and Bhaskar Gurubhai?

Context

The following additional facts are known:

1. Ustad Samiran never trained more than one of these students in the same year.

2. Acharya Raghunath did not train any of these students during 2015-2018, as well as during 2021-24.

3. Ananya and Devendra were never Gurubhai; neither were Bhaskar and Charu. All other pairs of musicians were Gurubhai for exactly 2 years.

4. In 2013, Ananya and Bhaskar started their trainings under Pandit Meghnath and under Ustad Samiran, respectively.

CAT 2025 · Slot 2

Hard

In which year did Charu begin her training under Pandit Meghnath?

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