Question

# 2. A mountain in Marion County is losing

elevation at a rate of 6% every decade. If the
current elevation is 1200 meters, how tall will the
mountain be after 7 decades

Answer 1

To answer this question, you cannot do it all at once. Since the percentage will change every year because of how percents work, you must do seven calculations for each of the seven decades.

To decrease a number by 6%, you multiply it by 0.94, which is the same as finding 94% of that number, as you have taken 60% away.

1. 1200*0.94 = 1128

2. 1128*0.94 = 1060.32

3. 1060.32*0.94 = 996.7008

4. 996.7008*0.94 = 936.898752

5. 936.898752*0.94 = 880.68482688

6. 880.68482688*0.94 = 827.843737267

7. 827.843737267*0.94 = 778.173113031

You probably don't need 9 decimal places, so we can round to 778.17.

After seven decades, the mountain will be 778.17 meters.