Interview Q&A / Aptitude
Aptitude interview questions
Quantitative shortcuts for placement tests: percentages, time and work, and more.
Prefer rapid revision? Practise Aptitude short interview answers →
- ₹10,000 is lent partly at 8% and partly at 12% simple interest. The total interest for one year is ₹960. How much was lent at each rate?
₹6,000 at 8% and ₹4,000 at 12%. The overall rate is 960/10,000 = 9.6%. Alligation gives (12 - 9.6) : (9.6 - 8) = 2.4 : 1.6 = 3 : 2.
IntermediateQuick answer1 min read - A sum at compound interest amounts to ₹6,050 in 2 years and ₹6,655 in 3 years. Find the rate and the principal.
Rate = 10% and principal = ₹5,000. The third year's interest is 6,655 - 6,050 = ₹605, which is 10% of ₹6,050. Then P = 6,050 / (1.1)^2 = 6,050 / 1.21 = ₹5,000.
IntermediateQuick answer1 min read - What is the rule of 72, and how long does money take to double at 9% compound interest?
Doubling time is roughly 72 divided by the annual rate in percent. At 9% that is 72 / 9 = 8 years. The exact answer is log 2 / log 1.09, about 8.04 years, so the rule is very close.
IntermediateQuick answer1 min read