Computer Knowledge / Quantitative Aptitude
Computer knowledge
The computer portion is factual and shallow: generations and hardware, input/output devices, memory hierarchy (registers → cache → RAM → secondary storage), units (1 KB = 1024 bytes), number-system conversion, operating-system basics, MS Office shortcuts and file extensions, networking (LAN/WAN, IP address, topologies, HTTP/FTP/SMTP), internet and e-mail, DBMS keys, and security terms such as phishing, firewall and malware.
Quantitative aptitude
Arithmetic carries the most marks: percentage, ratio and proportion, average, profit and loss, simple and compound interest, time–work, time–speed–distance, trains and boats, mixtures, mensuration, and data interpretation. Algebra, number series and basic probability appear in smaller numbers. Data interpretation is the highest-yield topic per hour because one table feeds five questions.
Formulae to keep ready
- Successive change: net % = a + b + ab/100.
- CI − SI for two years = P(r/100)².
- Combined work: 1/T = 1/A + 1/B.
- Average speed over equal distances = 2xy/(x+y), not (x+y)/2.
- Sphere volume 4/3πr³; cylinder πr²h.
Worked example
A finishes a job in 12 days, B in 18 days. LCM of 12 and 18 is 36 units of work. A does 3 units/day, B does 2 units/day, together 5 units/day, so time = 36/5 = 7.2 days. The fraction method gives the same value but costs more time under pressure.
Traps
Adding successive percentages directly; using the arithmetic mean for average speed; computing profit percentage on selling price instead of cost price; rounding early in data-interpretation questions that ask for "approximately".