Question

There is a certain number, whose value is unknown. But it is known that when $5$ is added to that number, we get $15$. What is the value of the number?

• A. $12$
• B. $11$
• C. $9$
• D. $10$

Answer 1

The correct option is D $10$

Let us take the number with the unknown value to be $x$.
Now, when we add $5$ to that number, we get $x+5$.
We know that when we add $5$ to that number, we get $15$.
Hence, $x+5=15$
To find the value of the unknown quantity, i.e., $x$, we need to subtract $5$ on both sides of the equation
$x+5-5=15-5$
$x=10$