Get Answers to all your Questions

header-bg qa

In a bank, principal increases at the rate of 5% per year. In how many years Rs. 1000 doubles itself?

 

  • Option 1)

    20 \log_{10} \: 2

  • Option 2)

    20 \log_{e} \: 2

  • Option 3)

    20

  • Option 4)

    None of these

 

Answers (1)

best_answer

 

Linear Differential Equation -

\frac{dy}{dx}+Py= Q

- wherein

P, Q are functions of x alone.

 

  given that \frac{dp}{dt}=P.\frac{dr}{dt}

\therefore\int_{P}^{2P}\frac{dP}{P}={\int_{0}^{t}}dt \times \frac{1}{20}     where \frac{dr}{dt} =5\% = \frac {5}{100}= \frac{1}{20} 

\therefore 20 \log P |_{2P}^{P}=t

\therefore 20 \log _{e}2=t

 


Option 1)

20 \log_{10} \: 2

Incorrect

Option 2)

20 \log_{e} \: 2

correct

Option 3)

20

Incorrect

Option 4)

None of these

Incorrect

Posted by

prateek

View full answer