Question

Two years ago, a plant was 192 cm tall. At present its height is 243 cm. Find the rate of its growth.

Answer 1

Given, present height, A = 243 cm

Time, T = 2 years

Height 2 years ago, P = 192 cm

Amount, `A = P(1 + R/100)^T`, where P is the principal, R is the rate of interest and T is the time period

∴ `192(1 + r/100)^2 = 243`

⇒ `(1 + r/100)^2 = 243/192`

⇒ `(1 + r/100)^2 = 81/64`

⇒ `(1 + r/100)^2 = (9/8)^2`

⇒ `1 + r/100 = 9/8`

⇒ `r/100 = 9/8 - 1`

⇒ `r/100 = (9 - 8)/8`

⇒ `r/100 = 1/8 xx 100`

⇒ r = 12.5

Hence, the rate of growth is 12.5%.