Percentage Help !!?

Question

Im a little confused as to how to find the answer. I am able to do it with only 2 numbers but the third number has throws me off.
What was the percent increase in the population in South America from 1900 to 2000?
1900-38,000,000,
1950-111,000,000,
2000-515,000,000

if it was only 2 say years 2000 and 1950 the equation would be
(515,000,000-111,000,000)/111,000000x100%
so what do I do when a third number is added ? does that make any sense ?

its x 100 % not 1... sorry

Answer 1

The 3 numbers show you the growth over the period. The population approx. tripled from 1900 to 1950, and then it really grew by almost 5 times from 1950 to 2000. That's a huge amount of growth over a 50 yr time period. Can you imagine what would happen if your city grew by 5 times its population over 50 years? The schools, the water supply, the housing, the sewers??

But having said that, the percent increase is calculated taking the begining & ending numbers of the period
so from 1900 to 2000 the growth was 515 M minus 38 M
=515-38=477M
The percentage growth is 477/38 *100%= 1255%
(yes, that's over 1000%, or more than 10 times the original population)

Answer 2

i think probably the 1950 is to throw u off. just use the two years , 2000 and 1900.

Answer 3

"percentage change from 1900 to 2000" means that the 1900 figure, 38,000,000, is your base of comparison.

population in 2000 = 515,000,000
change from 1900 = 515,000,000 - 38,000,000 = 477,000,000

percentage change = change / 38,000,000
= 477,000,000/38,000,000
= 1255%

Answer 4

They want you to learn to determine what information to use. You need to just ignore 1950 data. In the real world you often have more info. than what is useful.

Answer 5

from 1900 to 200 there was ancrease of 477,000,000
divide this by what you started with 38,000,000
12.55%