The difference in the sales of cellular phones for the years 1997 and 1999 is ?

The lowest rate of change for

For year 1997 and 1998 = ((48000 - 40000) / 40000) x 100 = 20%

For year 1999 and 2000 = ((30000 - 25000) / 25000) x 100 = 20%

is exhibited by both option (A) and (B).

The sum of sales of cellular phones in the years 1999 and 2001 is equal to that in ?

The sum of sales in the two years is 30,000 + 18,000 = 48,000, which is the sales value for 1997.

The percentage increases in sales from 2001 to 2002 was ?

The percentage increase exhibited is

((40 - 18)/18) x 100 = 122 % approximately.