2. Sample Papers
  3. KVPY

KVPY Sample Paper KVPY Stream-SX Model Paper-16

  • question_answer
    A two month study on a population of 500 rats showed that the emigration of individuals from the population was 1.5 times the rate of immigration. At the same time the birth rate was found to be two times the rate of death. If the number of emigrants during the period of study was 75 and the birth rate was 10%, what would be the number of rat individuals in the population at the end of the study?

    A) 500

    B) 1000

    C) 900

    D) 1500

    Correct Answer: A

    Solution :

    Immigration [I] = x
    Emigration [E] = 1.5x
    Death rate [D] = y
    Birth rate [B] = 2y
    Number of emigrants = 75
                            1.5 x=75
                            \[\operatorname{x}=\frac{75}{1.5}=50\]
    Birth rate [B] = \[2y=\text{ }10%\]
                            \[y=5%\]
    Number of dead individuals \[=\text{ }500\times \frac{5}{100}\]
                                         = 25
    Number of new births \[\left( 2y \right)=2\times 25=50\]
    Change in Population Size = (Births\[+\]Immigration)-(Deaths + Emigration) \[=\left( 50+50 \right)-\left( 25+75 \right)=0\]
    The number of rat individuals in the population at the end of the study
    \[=500+0=500\]


You need to login to perform this action.
You will be redirected in 3 sec spinner