jmc

Question

Two weeks ago, Alice came home from vacation and noticed that a bean plant was growing in her garden. Today, the stalk is 452 centimeters tall, and Alice observed that its height increases by 5% every day. How tall was the plant 2 weeks ago when she first noticed it growing? Express your answer as a decimal to the nearest tenth.

Accepted Answer

One week is equal to 7 days, and the plant grows by 5% each day. We can work backwards to find the previous size of the plant. We can reverse the compound interest formula to solve this problem, as if the plant loses five percent of its height every day for 14 days. So the height of the plant two weeks ago is equal to 452(1+0.05)^14= 4521.98=228.29So, the bean plant was 228.3 centimeters tall when Alice first found it.