$\sqrt{44944} + \sqrt{52441} = x$
Aptitude
Square Root and Cube Root
Difficulty: Medium
Choose an option
-
A17
-
B312
-
C441
-
D485
-
ENone of these
Answer
Correct Answer: 441
Explanation
### Concept & Strategy
Solve this by approximating the individual square roots using their unit digits and bounding them between known multiples of $10$.
Base approximation logic:
$$ \text{Find bounds } (10x)^2 < N < (10(x+1))^2 $$
### Step-by-Step Solution
- **Part 1: Find $\sqrt{44944}$**
- Unit digit is $4$, so the root ends in $2$ or $8$.
- Find base boundaries: $200^2 = 40000$ and $220^2 = 48400$. $210^2 = 44100$.
- $44944$ is slightly larger than $44100$.
- This points to the root being $212$.
- **Part 2: Find $\sqrt{52441}$**
- Unit digit is $1$, so the root ends in $1$ or $9$.
- Find base boundaries: $220^2 = 48400$ and $230^2 = 52900$.
- $52441$ is very close to $52900$.
- This means it is at the higher end of the range, pointing to $229$.
- **Part 3: Addition**
- Sum the two calculated roots: $212 + 229 = 441$.
### Exam Strategy & Shortcut
Use unit digit analysis for the final sum. The first root ends in $2$. The second root ends in $9$. The sum of the unit digits is $2 + 9 = 11$, which means the final answer must end in $1$. Among the given options, only $441$ ends in $1$.
### Common Pitfall
Getting bogged down in long division for square roots. Even if you aren't entirely sure of the exact roots, estimating them as $\sim 212$ and $\sim 230$ gives a sum around $442$, making $441$ the obvious answer by approximation alone.
### Final Answer
Therefore, the correct answer is 441.