## 268. Math Puzzle $9 / 87$

At the closing ceremony of a Pioneer camp, a 150-liter soda keg was tapped. Unfortunately, it was a bit cooler than expected that day, so at the end of the event, 20 liters more soda remained in the keg than had been served.

How many liters did the Pioneers drink?
$x+(x+20)=150 ; x=65$

At the graduation ceremony, 65 liters of lemonade were served.