🔍 Key Concepts

• Flammable (explosive) limits are defined by a lower flammable limit (LFL) and an upper flammable limit (UFL). • Typical motor gasoline vapor in air has a relatively wide flammable range compared to many other fuels. • Think about which range looks realistic for a fuel that is commonly involved in vapor explosions in confined spaces.

💭 Think About

• Which choice shows a range that is neither too narrow nor too close together, given how easily gasoline vapors ignite? • Consider that gasoline vapors can ignite at fairly lean mixtures (low % in air) and remain flammable up to fairly rich mixtures—which option best represents that behavior? • Eliminate any range that seems unrealistically tight or that suggests gasoline only burns in a very narrow band of concentrations.

✅ Before You Answer

• Verify the approximate LFL and UFL for gasoline vapors from standard marine firefighting or tanker safety references. • Check which option reflects a lower limit a bit above 1% and an upper limit in the mid‑single digits to low double digits—this is the ballpark you should be expecting. • Confirm that the selected range is consistent with gasoline being considered a highly flammable liquid with vapors that pose an explosion risk in many common situations.