Coins in the ratio 2 : 3 : 4 — Aptitude Question
Coins in the ratio 2 : 3 : 4: A bag holds ₹1, 50-paise and 25-paise coins in the ratio 2 : 3 : 4 by count, worth… Answer and worked solution on CodeKairo.
- Topic: Ratio & Proportion
- Section: Quantitative Aptitude
- Difficulty: Medium
- Time target: 75 seconds
Question
A bag holds ₹1, 50-paise and 25-paise coins in the ratio 2 : 3 : 4 by count, worth ₹90 in total. How many 50-paise coins are there?
Options
- 40
- 60
- 80
- 90
Show the answer and the worked solution
Correct answer: B. 60
Worked solution
- One set of coins (2 rupee coins, 3 fifty-paise, 4 twenty-five-paise) is worth 2 × 1 + 3 × 0.5 + 4 × 0.25 = ₹4.50.
- Number of sets = 90 ÷ 4.5 = 20.
- Fifty-paise coins = 3 × 20 = 60.
Answer: 60.
The idea
When counts are in a ratio but the question is about value, price one 'unit set' of the ratio and see how many sets the total buys. Never convert the count ratio to a value ratio in your head.
Shortcut. Back-substitute: 60 fifty-paise coins means 40 rupee coins and 80 25-paise coins, worth 40 + 30 + 20 = ₹90.
Common trap. 40 — the number of ₹1 coins (2 parts × 20 sets), read from the wrong place in the ratio.