Arithmetic and Basic Computer Knowledge
Arithmetic and basic computer knowledge test numerical fluency and everyday computer use. Arithmetic includes percentage, ratio, average, interest, speed and time; computer questions cover hardware, software, memory, office tools and the internet.
Core rules
- Percentage change uses the original value as base. Simple interest is PRT/100; compound interest grows on principal plus accumulated interest. Average is sum divided by count.
- Speed = distance/time; convert units consistently. Ratio problems should keep the same order of terms.
- Computer hardware is physical; software is programs. RAM is volatile working memory; ROM is non-volatile. One byte equals 8 bits. Input devices include keyboard and mouse; output devices include monitor and printer.
Worked example
Find simple interest on 5000 rupees at 8% per annum for 2 years. SI = P × R × T / 100 = 5000 × 8 × 2 / 100 = 800 rupees. The amount is 5000 + 800 = 5800 rupees. Compound interest would be higher because interest is added to principal.
Traps
A 20% increase followed by a 20% decrease does not return to the original value. Use the original base for percentage change. Do not confuse RAM with hard disk storage. Check whether interest is simple or compound and whether time is in months or years.