A tree increases annually by 1/8th of its height. By how much will it increase…
2022
A tree increases annually by 1/8th of its height. By how much will it increase after 2 years, if it stands today 64 cm high?
- A.
81 cm
- B.
75 cm
- C.
74 cm
- D.
72 cm
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Correct answer: A
Solution:
The tree grows by one-eighth of its current height each year. Compute either year-by-year or use the compound factor (1 + 1/8).
Year-by-year method: Year 1: 64 + 64*(1/8) = 64 + 8 = 72 cm. Year 2: 72 + 72*(1/8) = 72 + 9 = 81 cm.
Compound factor method: Multiply by (1 + 1/8) twice: 64 * (9/8)^2 = 64 * (81/64) = 81 cm.
Answer: 81 cm