Alexandria is 45. She is also 6 less than three times Kira's age. How old is Kira?

Question

1438 views around the world

You can reuse this answer
Creative Commons License

Answer 1 · 2016-11-30T12:44:27

$17$ $17$

Let's make an equation

Let the age of Kira be $k$ $k$
$3$ $3$ times her age would be $3 k$ $3k$
And Alexandria's age would equal $3 k - 6$ $3k-6$

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Then,

$\to 45 = 3 k - 6$ $rarr45=3k-6$

Add $6$ $6$ both sides

$\to 45 + 6 = 3 k - 6 + 6$ $rarr45+6=3k-6+6$

$\to 51 = 3 k$ $rarr51=3k$

Divide both sides by $3$ $3$

$rarr51/3=(cancel3k)/cancel3$

$color(green)(rArr17=k$

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

So Kira's age is $17$