Two sums, equal after different times — Aptitude Question
Two sums, equal after different times: ₹1,000 is lent at 5% simple interest. After how many years will the amount… Answer and worked solution on CodeKairo.
- Topic: Simple & Compound Interest
- Section: Quantitative Aptitude
- Difficulty: Easy
- Time target: 50 seconds
Question
₹1,000 is lent at 5% simple interest. After how many years will the amount be ₹1,400?
Options
- 6
- 7
- 8
- 10
Show the answer and the worked solution
Correct answer: C. 8
Worked solution
- Interest required = 1,400 − 1,000 = ₹400.
- Yearly interest = 5% of 1,000 = ₹50.
- Years = 400 ÷ 50 = 8.
Answer: 8.
The idea
Find the interest needed, then divide by the yearly amount. Under simple interest every year contributes equally.
Shortcut. ₹400 is 40% of 1,000, and 40% at 5% a year takes 40 ÷ 5 = 8 years.
Common trap. 7 — compounding the 5% (1.05⁷ ≈ 1.407 reaches ₹1,400 in about 7 years); simple interest adds a flat ₹50 a year.
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