In the week that ended June 19, the U.S. commercial crude oil inventory decreased by 3.8 million barrels. Now if the inventory was 353.9 million barrels in the week that followed, what was the U.S. crude oil inventory before the decline?

To calculate the U.S. crude oil inventory before the decline, we need to subtract the decrease of 3.8 million barrels from the inventory of 353.9 million barrels in the following week. Let's denote the initial inventory before the decline as X.
X - 3.8 million barrels = 353.9 million barrels.

To isolate X, we can add 3.8 million barrels to both sides of the equation:
X = 353.9 million barrels + 3.8 million barrels = 357.7 million barrels.

Therefore, the U.S. crude oil inventory before the decline was approximately 357.7 million barrels.