Question

I celebrate my birthday on ${12}^{th}$ January on earth. On which date would I have to celebrate my birthday if I were on a planet where binary system is being used for counting. (The number of days, months and years are same on both the planets.)

• A. ${11}^{th}Jan$
• B. ${111}^{th}Jan$
• C. ${110}^{th}Jan$
• D. ${1100}^{th}Jan$

Answer 1

The correct option is D ${1100}^{th}Jan$

On earth (a decimal system is used).
Birthday is on ${12}^{th}$ Jan
The ${12}^{th}$ day on the planet where binary system is being used will be called
$(12{)}_{10}=(?{)}_2=\frac{1}{2^3}\frac{1}{2^2}\frac{0}{2^1}\frac{0}{2^0}$
i.e., ${1100}^{th}$ day on that planet
So, ${12}^{th}$ January on earth = ${1100}^{th}$ January on that planet
$\Rightarrow$ Correct answer is option (d)