Three plots having areas 110, 130 and 190 square metres are to be subdivided into flower beds of equal size. If the breadth of a bed is 2 metre, the maximum length of a bed can be
Aptitude
HCF and LCM
Difficulty: Easy
Choose an option
-
A5 m
-
B11 m
-
C13 m
-
D19 m
Answer
Correct Answer: 5 m
Explanation
### Concept & Highest Common Factor (HCF)
To divide different total areas into equal-sized beds of maximum possible area, find the Highest Common Factor (HCF) of the given total areas.
$$ \text{Area of Bed} = \text{Length} \times \text{Breadth} $$
### Step-by-Step Solution
1. **Find the maximum area of a single flower bed:**
- The areas of the plots are $110$, $130$, and $190$ sq. m.
- The maximum area of an equal-sized bed must perfectly divide all three plot areas.
- $\text{Maximum Area} = \text{HCF}(110, 130, 190)$.
- The HCF of $110$, $130$, and $190$ is $10$ (since $11 \times 10 = 110$, $13 \times 10 = 130$, $19 \times 10 = 190$, and $11, 13, 19$ are prime to each other).
- So, the maximum area of a flower bed is $10 \text{ sq. m}$.
2. **Find the maximum length of the bed:**
- The breadth of the bed is given as $2 \text{ m}$.
- $\text{Area} = \text{Length} \times \text{Breadth} \Rightarrow 10 = \text{Length} \times 2$.
- $\text{Length} = \frac{10}{2} = 5 \text{ m}$.
### Exam Strategy & Shortcut
Recognize instantly that dividing distinct groups into maximum equal components requires the HCF. The trailing zero in 110, 130, 190 makes 10 the obvious HCF. Since Area = $10$ and Breadth = $2$, Length = $5$. This can be solved mentally in 5 seconds.
### Common Pitfall
A common mistake is trying to find the LCM instead of the HCF, or forgetting to divide the resulting HCF (area) by the given breadth to find the length.
### Final Answer
Therefore, the correct answer is **5 m**.