Answer:
c) 160,000
Step-by-step explanation:
Since we know that the population of both city x and city y are equal in 2015, we can use the population growth of population of city x to find the population in 2015:
120,000 x 1.2 = 144,000.
Now, since we know that City Y's population decreased 10% from 2010 to 2015, we can divide the 2015 population of city Y (which is the same as city x - 144,00) by 1 - decrease rate to find city y's population in 2010:
1 - .1 = .9
144,000 / .9 = 160,000
I hope this helps!
-TheBusinessMan