The number of blogs (or weblogs) grew rapidly for several years. According to one report, since early 2004 the number of blogs has doubled in size every six months.

What is the percentage increase from March 2004 to March 2006?

1500%

Step-by-step explanation:

From March 2004 - March 2006, this is 2 years. The number of "6-month" period there are in 2 years is:

2 * 12 = 24 months

24/6 = 4 "6 month periods"

So, it doubles "4" times in that time frame.

Let Initial population be 100 (In March 2004).

1 times double = 100 * 2 = 200

2 times double = 200 * 2 = 400

3 times double = 400 * 2 = 800

4 times double = 800 * 2 = 1600

So, population goes from 100 to 1600. How much percentage increase is that?

To get percentage increase, we find the increase and divide by original (initial amount). Then multiply by 100 to get percentage. So,

1600 - 100 = 1500 increase

1500/100 = 15

15 * 100 = 1500%