Question

A two digit number is such that the sum of itself and the number obtained when its digits are reversed is 55. Using the given data, write the simplest equation possible in two variables.

• A. $x+\frac{1}{x}=55$
• B. $x+y=5$
• C. $x+5=y$
• D. $2x+2y=55$

Answer 1

The correct option is B

$x+y=5$

Any two digit number can be written as: $10x+y$
where $x$ is the tens digit and $y$ is the ones digit.

The number obtained by reversing the digits of the two digit number can be represented as $10y+x$.

According to the question, the sum of the number and the number obtained by reversing its digits is 55.
$(10x+y)+(10y+x)=55$
$\Rightarrow 11x+11y=55$
$\Rightarrow x+y=5$