Quantitative Reasoning and Mathematics
What is tested
Quantitative Reasoning and Mathematics covers arithmetic, fractions, percentages, ratios, basic algebra, geometry, unit conversion, and word problems set in naval contexts such as fuel burn, watch rotations, and speed. Expect no calculator, so estimation and clean setup matter.
Core rules
- Define the unknown and translate each phrase into an operation.
- Keep units attached: 1 knot = 1 nautical mile per hour; 1 nautical mile = 1.852 km.
- Percent change is (new − old) ÷ old. 'Percent of' and 'percent more than' are different.
- Backsolve from choices when the algebra is slow; substitute to check.
- Geometry: triangle area = ½bh; circle area = πr²; Pythagorean theorem for right triangles.
- Estimate first to catch magnitude errors.
Worked example
A destroyer burns 1,200 L of fuel in 8 hours at 15 knots. At the same rate, how much fuel does it burn in 5 hours? Rate = 1,200 ÷ 8 = 150 L/h. Fuel = 150 × 5 = 750 L. The 15-knot figure is extra information because the rate is already given in liters per hour.
Traps that cost marks
Mixing knots with km/h; using diameter as radius; treating a 20% decrease followed by a 20% increase as no change; and averaging two averages without weighting. Check whether the question asks for a rate, a time, or a total.