A lake currently has a depth of 30 meters. As sediment builds up in the lake, its depth decreases by 2% per year. This situation represents:
A. exponential decay
B. exponential growth

The rate of growth or decay, r, is equal to:
A. 1.02
B. 0.02
C. 0.98

So the depth of the lake each year is times the depth in the previous year.
A. 0.98
B. 0.02
C. 1.02

It will take between years for the depth of the lake to reach 26.7 meters.
A. 3 and 4
B. 11 and 12
C. 9 and 10
D. 5 and 6