Question #901ee

Feb 13, 2017

The two numbers are $3$ and $6$

Explanation:

Let's call the two numbers $n$ and $m$.

Because one number is twice the other number we can write this as:

$n = 2 m$

And then, because their sum is $9$ we can write:

$n + m = 9$

Next, we can substitute $2 m$ from the first equation for $n$ in the second equation and solve for $m$:

$n + m = 9$ becomes:

$2 m + m = 9$

$3 m = 9$

$\frac{3 m}{\textcolor{red}{3}} = \frac{9}{\textcolor{red}{3}}$

$\frac{\textcolor{red}{\cancel{\textcolor{b l a c k}{3}}} m}{\cancel{\textcolor{red}{3}}} = 3$

$m = 3$

We can now substitute $3$ for $m$ in the first equation and calculate $n$:

$n = 2 m$ becomes:

$n = 2 \times 3$

$n = 6$

The solution is $m = 3$ and $n = 6$