###Human: 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?, ### Assistant: Let J = Josh's distance
2J = Selena's distance
J + 2J = 36
3J = 36 miles
J = 12
2J = 24 miles
Selena ran 24 miles. 
 So the answer is :  24