[Answer] How many gallons of paint does it take to cover the outside surface of the White House?

Step 1 : Introduction to the question "How many gallons of paint does it take to cover the outside surface of the White House?"

...The White House is one of the most iconic buildings in the world. Every U.S. president since John Adams has called the White House home during his administration. Congress named the White House as an American national museum in the 1960s, preserving its antiquities for coming generations. To maintain the White House in good condition requires constant upkeep. To cover the president's home with a new coat of paint requires 570 gallons of paint. The White House interior includes 132 rooms, 35 bathrooms, 147 windows, 28 fireplaces, 412 doors, 8 staircases and 3 elevators. Source: WhiteHouse.gov

[Ans] How many gallons of oil does a standard barrel hold?

Step 1 : Introduction to the question "How many gallons of oil does a standard barrel hold?"

...A barrel, cask, or tun is a hollow cylindrical container, traditionally made of wooden staves bound by wooden or metal hoops. Traditionally, the barrel was a standard size of measure referring to a set capacity or weight of a given commodity. Barrel.

 What is Beral? A barrel is one of several units of volume applied in various contexts; there are dry barrels, fluid barrels (such as the UK beer barrel and US beer barrel), oil barrels and so on.