Arithmetic Reasoning
What to know
Arithmetic Reasoning is word problems, not bare computation. The arithmetic is usually easy; the real test is translation. Expect percentages and percent change, ratios and proportions, unit rates, averages, distance = rate × time, work rates, simple interest, and money or measurement conversions. Everything is solvable without a calculator, so correct answers are usually round numbers.
Traps
- Percent of versus percent change. Percent change is always measured against the original amount, not the new one.
- Unit mismatch. Minutes hidden inside hours and cents hidden inside dollars cause more wrong answers than any other error.
- Answering the wrong quantity, such as finding what was used when the question asks what remains.
- Weighted averages. A group of 10 averaging 80 combined with a group of 30 averaging 90 is not 85.
- Distractor answers that match a partial step of the problem.
Rule of thumb
Write the units next to every number before computing, and convert first, solve second. If your answer's units do not match the units the question asks for, stop and re-read.
Worked example
A car travels 150 miles in 3 hours. At the same speed, how far does it go in 5 hours? Rate = 150 ÷ 3 = 50 miles per hour. Distance = 50 × 5 = 250 miles. Trap answers include 90 (adding the hours) and 30 (150 ÷ 5). Naming the rate in miles per hour makes the correct operation obvious.