Question

Answer the attachment............




Don't spam!!!!!



​

Answer 1

At $\large\rm { t = 1 s}$

N = 90

$\large\rm { 90 = N \cdot e^{-kt}}$

$\large\rm{ e^{-k} = \frac{90}{100}}$

$\large\rm { e^{-k} = \frac{9}{10} .........(1) }$

$\large\rm { At \ t = 2 \ s}$

$\large\rm { N = N \cdot e^{-kt}}$

$\large\rm { N = 100 ( e^{-2k})}$

$\large\rm { N = 100 ( e^{-k})^{2} ......(2)}$

$\large\rm { = \frac{9}{10} ......(2)}$

$\large\rm { N = 100 ( \frac{9}{10})^{2}}$

$\large\rm{\bold { 81 }}$ is the required answer.

Answer 2

hope this helps you mate