A big container is 50% full with water. If 20 liters of water is added, the container becomes 3/4 full. What is the capacity of the big container in liters?  Choices
A) 80 B) 90 C) 100 D) 110 E) 120
20 liters is 25% of the capacity C.   20 = 0.25C   C = 80 liters.   The answer is 80.
<result>A</result>
A big container is 50% full with water. If 20 liters of water is added, the container becomes 3/4 full. What is the capacity of the big container in liters?