If $[p]$ means the greatest integer less than or equal to $p$, then $\left[-\frac{1}{4}\right] + \left[4\frac{1}{4}\right] + [3]$ is equal to:
Aptitude
Simplification
Difficulty: Easy
Choose an option
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A4
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B5
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C6
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D7
Answer
Correct Answer: 6
Explanation
### Concept & Logic
This problem introduces the **Greatest Integer Function**, also known as the floor function, denoted by $\lfloor p \rfloor$ or $[p]$.
The rule is simple: $[p]$ outputs the largest integer that is less than or equal to $p$. For positive decimals, you effectively drop the decimal. For negative decimals, you must round down to the next most negative integer (moving left on the number line).
### Step-by-Step Solution
Evaluate each term individually using the definition of the greatest integer function:
* **Step 1: Evaluate $\left[-\frac{1}{4}\right]$**
The value $-\frac{1}{4}$ is $-0.25$. The integers surrounding $-0.25$ are $-1$ and $0$.
Since the function returns the integer *less* than or equal to the number, we round down to $-1$.
$$\left[-\frac{1}{4}\right] = -1$$
* **Step 2: Evaluate $\left[4\frac{1}{4}\right]$**
The value $4\frac{1}{4}$ is $4.25$. The greatest integer less than or equal to $4.25$ is $4$.
$$\left[4\frac{1}{4}\right] = 4$$
* **Step 3: Evaluate $[3]$**
Since $3$ is already an integer, the greatest integer less than or equal to $3$ is simply $3$ itself.
$$[3] = 3$$
* **Step 4: Sum the Values**
Now, add the three evaluated components together:
$$-1 + 4 + 3 = 6$$
### Exam Strategy & Shortcut
Visualize a number line. For any number $p$, $[p]$ simply asks you to "slide left" until you hit the first whole number. For $4.25$, sliding left hits $4$. For $-0.25$, sliding left crosses zero and hits $-1$.
### Common Pitfall
The most frequent mistake is assuming that $\left[-\frac{1}{4}\right]$ equals $0$. Students often incorrectly truncate the decimal (dropping the $.25$) instead of finding the integer *less* than the value. Remember, $0$ is greater than $-0.25$, so it violates the rule.
### Final Answer
**Therefore, the correct answer is 6.**