OAR Math Skills: Word Problems Flashcards

An aircraft carrier travels at 28 knots for 4 hours, then at 18 knots for 3 hours. What is the total distance covered in nautical miles?

Answer: 166 nm

Distance = (28 x 4) + (18 x 3) = 112 + 54 = 166 nautical miles.

A training course costs $4,500. The Navy covers 80% and the officer pays the rest in 6 equal monthly installments. How much is each installment?

Answer: $150

Officer's share = 20% of $4,500 = $900; monthly installment = $900 / 6 = $150.

A pump drains a 12,000-gallon tank at 250 gallons per minute. A second pump draining 150 gallons per minute starts 10 minutes after the first. How many total minutes from start until the tank is empty?

Answer: 34 minutes

After 10 min, pump 1 removes 2,500 gal (9,500 remain); combined rate = 400 gpm; 9,500 / 400 = 23.75 min; total = 33.75 min, rounded up to 34 minutes.

A jet uses 1,800 lb of fuel per hour cruising and 2,400 lb per hour climbing. A mission has 20 minutes of climb and 2 hours of cruise. How many pounds of fuel are used?

Answer: 4,400 lb

Climb fuel = 2,400 x (20/60) = 800 lb; cruise fuel = 1,800 x 2 = 3,600 lb; total = 4,400 lb.

If 5 technicians can service 15 aircraft in 3 days, how many technicians are needed to service 36 aircraft in 4 days?

Answer: 9

Rate = 15 / (5 x 3) = 1 aircraft per technician-day; tech-days needed = 36; technicians = 36 / 4 = 9.

A navigational chart uses a scale of 1 inch = 15 nautical miles. Two ports measure 6.4 inches apart. If a ship travels between them at 24 knots, how long does the trip take?

Answer: 4 hours

Actual distance = 6.4 x 15 = 96 nautical miles; time = 96 / 24 = 4 hours.

Two communications specialists can encode 45 and 30 messages per hour respectively. Working together, how long will it take them to encode 225 messages?

Answer: 3 hours

Combined rate = 45 + 30 = 75 messages per hour; time = 225 / 75 = 3 hours.