Question #901ee

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Answer 1 · 2017-02-13T02:13:06

The two numbers are $3$ $3$ and $6$ $6$

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

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

$n = 2 m$ $n = 2m$

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

$n + m = 9$ $n + m = 9$

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

$n + m = 9$ $n + m = 9$ becomes:

$2 m + m = 9$ $2m + m = 9$

$3 m = 9$ $3m = 9$

$\frac{3 m}{3} = \frac{9}{3}$ $(3m)/color(red)(3) = 9/color(red)(3)$

$(color(red)(cancel(color(black)(3)))m)/cancel(color(red)(3)) = 3$

$m = 3$

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

$n = 2m$ becomes:

$n = 2 xx 3$

$n = 6$

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