HCF of 1.75, 5.6 and 7 — Number System Aptitude Question
HCF of 1.75, 5.6 and 7: Find the HCF of 1.75, 5.6 and 7. Answer and worked solution on CodeKairo.
- Topic: Number System
- Section: Quantitative Aptitude
- Difficulty: Medium
- Time target: 75 seconds
Question
Find the HCF of 1.75, 5.6 and 7.
Options
- 0.07
- 0.35
- 0.7
- 1.75
Show the answer and the worked solution
Correct answer: B. 0.35
Worked solution
- Write them to two decimals: 1.75, 5.60, 7.00 → 175, 560, 700.
- HCF(175, 560, 700): 175 = 5² × 7, 560 = 2⁴ × 5 × 7, 700 = 2² × 5² × 7 → common part 5 × 7 = 35.
- Restore two decimal places: 0.35.
Answer: 0.35.
The idea
Never take an HCF of decimals directly. Pad every number to the same decimal length, treat them as integers, and shift the point back at the end. The same rule works for LCM.
Shortcut. Try the options from the largest: 1.75 does not divide 5.6 (3.2 times) and 0.7 does not divide 1.75 (2.5 times), but 0.35 goes into 1.75, 5.6 and 7 exactly 5, 16 and 20 times.
Common trap. 0.07 — writing 1.75, 5.6 and 7 as 175, 56 and 7 without padding to two decimals, which gives HCF 7 and then 0.07 after shifting two places.