The population of a district increases by during the first year and decreases by during the second year. If the present population of the district is , then two years ago it was:
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Solution & Step-by-step Explanation
Let the population of the district two years ago be .
1. After the first year, the population increases by :
2. After the second year, the population decreases by , which is equal to the present population ():
3. Solve for :
Simplify the calculation step-by-step:
Notice that .
Next, .
1. After the first year, the population increases by :
2. After the second year, the population decreases by , which is equal to the present population ():
3. Solve for :
Simplify the calculation step-by-step:
Notice that .
Next, .