Question

From 1970 to 1980, the population of New City increased by 20%. From 1980 to 1990, the population of New City increased by 50%. What was the percent increase in the population of New City from 1970 to 1990? Please explain how you got this answer!

Answer 1

assuming there's no typo, the answer is found in the first sentence

"From 1970 to 1990, the population of New City increased by 20%"

Answer 2

did you mean
"From 1970 to 19\(\bf \text{80}\), the population of New City increased by 20%.

From 1980 to 1990, the population of New City increased by 50%." ?

Answer 3

I'm sorry, it was a typo! 1970 to 1980

Answer 4

Let's say the population in 1970 was 100 people

increase this by 20% to get _____ people

Answer 5

okay

Answer 6

what goes in the blank

Answer 7

is it 20?

Answer 8

20% of 100 is 20

but you add that to 100 to get 100+20 = 120

Answer 9

so when you increase 100 by 20%, you get to 120

Answer 10

okay

Answer 11

now increase 120 by 50% to get _____

Answer 12

180?

Answer 13

yep, so what's the percent increase when the population goes from 100 to 180?

Answer 14

80 percent!????

Answer 15

bingo

Answer 16

Thanks so much!!!!

Answer 17

you're welcome