If $$\log _2 x+\log _4 x+\log _8 x+\log _{16} x=\frac{25}{36}$$ and $$x=2^{\mathrm{k}}$$ then $$\mathrm{k}$$ is

The approximate value of $$\log _{10} 998$$ is (given that $$\log _{10} \mathrm{e}=0.4343$$ )

If the population grows at the rate of $$8 \%$$ per year, then the time taken for the population to be doubled is

(Given $$\log 2=0.6912$$)

Bismath has half life period of 5 days. A sample originally has a mass of 1000 mg, then the mass of Bismath after 30 days is