Arithmetic and Basic Computer Knowledge
Arithmetic and Basic Computer Knowledge tests numerical fluency and everyday digital competence. Arithmetic items are percentage, ratio, average, time–work, speed–distance, simple and compound interest, and data interpretation. Computer items cover hardware, operating systems, office software, networks, hospital information systems and basic security.
Arithmetic rules
Percentage change = (change ÷ original) × 100. Simple interest = P × R × T ÷ 100; compound amount = P(1 + R/100)^T. Work: if A finishes in 12 days and B in 18, together they do 1/12 + 1/18 = 5/36 per day, so 36/5 = 7.2 days. Average = sum ÷ count; for combined groups use weighted averages.
Computer basics
RAM is volatile working memory; ROM is non-volatile. An operating system manages hardware, files and processes. A LAN covers a small area; the internet is a network of networks. In a hospital information system, never share passwords, log out of unattended terminals, and treat patient data as confidential. Phishing is a fraudulent message designed to steal credentials.
Worked example
A vial contains 250 mg in 5 mL. How many mL give 400 mg? Concentration = 250 ÷ 5 = 50 mg/mL. Volume = 400 ÷ 50 = 8 mL. Check: 8 × 50 = 400 mg, so the dose is correct.
Traps
Convert units before calculating: 1 g = 1000 mg, 1 L = 1000 mL, 1 hour = 60 minutes. Compound interest is always more than simple interest for the same rate and time after the first year. Do not round a drug volume without checking the permitted range. In computer questions, save and save as are different operations.