Selena and Josh were running in a race. Together they ran 36 miles. Josh ran half of the distance that Selena ran. How many miles did Selena run?
Let J = Josh's distance
2J = Selena's distance.
J + 2J = 36
3J = 
<gadget id="calculator">36</gadget>
<output>36</output>
36 miles.
J = 
<gadget id="calculator">12</gadget>
<output>12</output>
12
2J = 
<gadget id="calculator">24</gadget>
<output>24</output>
24 miles.
Selena ran 24 miles.

<result>24</result>