How many minutes did Suranjan take to solve the third visual puzzle in the competition?

Puzzle	Type	Anirbid	Chandranath	Koushik	Suranjan
1				2
2				4
3				6
4				8
5				10
6				12
7				14
8				16
9				19
10				22

Koushik's completion times are read from the left chart.

His line steps up by one puzzle about every $2$ minutes early on and slows near the end, reaching:

$2,\,4,\,6,\,8,\,10,\,12,\,14,\,16,\,19,\,22$

His steady, clean steps make him the most reliable line to read first.

Puzzle	Type	Anirbid	Chandranath	Koushik	Suranjan
1	V			2
2	N			4
3	V			6
4	N			8
5	N			10
6	N			12
7	V			14
8	V			16
9	V			19
10	V			22

The Type column is filled using the right chart for Koushik.

His visual-puzzle count at each completion instant is:

after P1: $1$

after P2: $1$

after P3: $2$

after P4: $2$

after P5: $2$

after P6: $2$

after P7: $3$

after P8: $4$

after P9: $5$

after P10: $6$

---

The visual count increases exactly at puzzles $1,3,7,8,9,10$, so these are visual ($V$).

It stays unchanged at puzzles $2,4,5,6$, so these are number-based ($N$).

This gives total visual $=6$ and total number-based $=4$. The other three competitors' charts reproduce the same pattern, confirming the common sequence.

Puzzle	Type	Anirbid	Chandranath	Koushik	Suranjan
1	V	3		2
2	N	7		4
3	V	10		6
4	N	13		8
5	N	18		10
6	N	22		12
7	V	24		14
8	V	26		16
9	V	28		19
10	V	31		22

Anirbid's completion times are read from the left chart:

$3,\,7,\,10,\,13,\,18,\,22,\,24,\,26,\,28,\,31$

He finishes last overall, with all ten done at minute $31$.

Puzzle	Type	Anirbid	Chandranath	Koushik	Suranjan
1	V	3	4	2
2	N	7	7	4
3	V	10	10	6
4	N	13	13	8
5	N	18	16	10
6	N	22	19	12
7	V	24	22	14
8	V	26	24	16
9	V	28	26	19
10	V	31	28	22

Chandranath's completion times are read from the left chart:

$4,\,7,\,10,\,13,\,16,\,19,\,22,\,24,\,26,\,28$

Puzzle	Type	Anirbid	Chandranath	Koushik	Suranjan
1	V	3	4	2	3
2	N	7	7	4	6
3	V	10	10	6	10
4	N	13	13	8	13
5	N	18	16	10	16
6	N	22	19	12	20
7	V	24	22	14	22
8	V	26	24	16	24
9	V	28	26	19	26
10	V	31	28	22	29

Suranjan's completion times are read from the left chart:

$3,\,6,\,10,\,13,\,16,\,20,\,22,\,24,\,26,\,29$

---

The table is now complete. Every type and completion time is fixed by the two charts, with no ambiguity.

The puzzle sequence is $V,N,V,N,N,N,V,V,V,V$ (visual at $1,3,7,8,9,10$; number-based at $2,4,5,6$).

Total times are Koushik $22$, Chandranath $28$, Suranjan $29$, Anirbid $31$, so Koushik is the winner.

---

From the sequence, visual puzzles occupy positions $1,3,7,8,9,10$. Hence the third visual puzzle is puzzle $7$.

Suranjan finished puzzle $6$ at minute $20$ and puzzle $7$ at minute $22$.

Time on the third visual puzzle $=22-20=2$ minutes.

Answer: 2.