ASVAB Arithmetic Reasoning Practice Test 254227

Questions 5
Topics Factorials, Multiplying & Dividing Exponents, PEMDAS, Percentages, Rates

Study Guide

Factorials

A factorial has the form n! and is the product of the integer (n) and all the positive integers below it. For example, 5! = 5 x 4 x 3 x 2 x 1 = 120.

Multiplying & Dividing Exponents

To multiply terms with the same base, multiply the coefficients and add the exponents. To divide terms with the same base, divide the coefficients and subtract the exponents. For example, 3x2 x 2x2 = 6x4 and \({8x^5 \over 4x^2} \) = 2x(5-2) = 2x3.

PEMDAS

Arithmetic operations must be performed in the following specific order:

  1. Parentheses
  2. Exponents
  3. Multiplication and Division (from L to R)
  4. Addition and Subtraction (from L to R)

The acronym PEMDAS can help remind you of the order.

Percentages

Percentages are ratios of an amount compared to 100. The percent change of an old to new value is equal to 100% x \({ new - old \over old }\).

Rates

A rate is a ratio that compares two related quantities. Common rates are speed = \({distance \over time}\), flow = \({amount \over time}\), and defect = \({errors \over units}\).