Percentage change (rise/fall) in the production of Company Y in comparison to the previous year, for different years are:

For 1997 =		(35 - 25)	x 100		% = 40%.
		25

For 1998 =		(35 - 35)	x 100		% = 0%.
		35

For 1999 =		(40 - 35)	x 100		% = 14.29%.
		35

For 2000 =		(50 - 40)	x 100		% = 25%.
		40

Hence, the maximum percentage rise/fall in the production of Company Y is for 1997.

Average production of Company X in the period 1998-2000

=		1	x (25 + 50 + 40)		=		115		lakh tons.
		3					3

Average production of Company Y in the period 1998-2000

=		1	x (35 + 40 + 50)		=		125		lakh tons.
		3					3

Required ratio =	115 3	=	115	=	23	.
	125 3		125		25

Average production (in lakh tons) in five years for the three companies are:

For Company X =		1	x (30 + 45 + 25 + 50 + 40)		=	190	= 38.
		5				5

For Company Y =		1	x (25 + 35 + 35 + 40 + 50)		=	185	= 37.
		5				5

For Company Z =		1	x (35 + 40 + 45 + 35 + 35)		=	190	= 38.
		5				5

Average production of five years is maximum for both the Companies X and Z.

The percentages of production of Company Z to the production of Company Z for various years are:

For 1996 =		35	x 100		% = 140%.
		25

For 1997 =		40	x 100		% = 114.29%.
		35

For 1998 =		45	x 100		% = 128.57%.
		35

For 1999 =		35	x 100		% = 87.5%.
		40

For 2000 =		35	x 100		% = 70%.
		50

Clearly, this percentage is highest for 1996.

Percentage increase in the production of Company Y from 1996 to 1999

=		(40 - 25)	x 100		%
		25

=		15	x 100		%
		25

    = 60%.