Question

In a pond, last year there were $30$ lotus plants. Through reproduction, $25$ new lotus plants were added in one year while $8$ plants died. The birth and death rates for the lotus population respectively are ___ and ____ individuals per lotus per year.

• A. $0.83$, $0.26$
• B. $0.26$, $0.83$
• C. $0.25$, $0.80$
• D. $0.80$, $0.25$

Answer 1

Answer: (A)

Total number of plants (in the beginning) $= 30$
New plants added by reproduction $= 25$
Birth rate (of a population)
$=\frac{\text{New plants}}{\text{Total number of plants}}=\frac{25}{30}$
$= 0.83$ individuals per lotus per year
Number of plants died $= 8$
Death rate (of a population) $=\frac{\text{Number of deaths}}{\text{Total number of plants}}$
$=\frac{8}{30}=0.26$ individuals per lotus per year.