A container holds 15 liters. Approximately how many gallons is this, given that 1 gallon ≈ 3.785 liters?

There are about $3.785$ liters in a gallon, so the number of gallons is the number of liters divided by $3.785$: $\frac{15}{3.785}\approx3.96$, which is closest to $4.0$, choice B. A quick estimate: $4$ gallons is about $4\cdot3.785=15.14$ liters. Choice D ($56.8$) multiplies by $3.785$, converting in the wrong direction. Choice A ($3.0$) is a rough underestimate. Choice C ($5.7$) does not match any step. Because a gallon is larger than a liter, the same volume is a smaller number in gallons.