Pretty simple word problem, first to solve gets best answer?

Question

The use of iPods has increased in popularity. In 2001, there were 20 million people who used one. Assuming the use of iPods increases 10% annually, predict the number of people using an iPod in 2009.

Answer 1

It depends on whether you mean an exponential growth or a linear growth.

EXPONENTIAL GROWTH:

2001 --> 20 million
2002 --> 20 million x 1.10
2003 --> 20 million x (1.10)²
2004 --> 20 million x (1.10)^3
...
2009 --> 20 million x (1.10)^8

Answer is approximately:
42,871,776

LINEAR GROWTH:
2001 --> 20 million
2002 --> 20 million + 2 million (10%)
2003 --> 20 million + 2*(2 million)
2004 --> 20 million + 3*(2 million)
...
2009 --> 20 million + 8*(2 million)

Answer:
36 million

Answer 2

A = Pe^(rt), where
P = 20 million
r = 10% = 0.1
t = 2009 - 2001 = 8 years

So
A = 49.19206... million people

Answer 3

x 20
- -
20 100 x100=x400

x=4

40 million people will be having an iPod

Answer 4

N = P(1 + i)^n, where N = number of people using iPod in 2009,
P = 20M, i = 0.10, n = 8 (2009 - 2001 = 8).

Solution:
N = 20(1+ 0.01)^8
N = 20(1.01)^8
N = 21.66 M ANS


teddy boy

Answer 5

2001: 20 million
2002: 20 million*(1.1)
2003: 20 million*(1.1)^2
2004: 20 million*(1.1)^3
........................
2008: 20 million*(1.1)^7
2009: 20 million*(1.1)^8

I hope you understand what i'm going to say

Answer 6

If it simple why are you asking for answers??