Find the average of 205, 302, 108, 403 and 202
Aptitude
Average
Difficulty: Easy
Choose an option
-
A450
-
B1225
-
C244
-
D1220
Answer
Correct Answer: 244
Explanation
### Concept & Formula
The arithmetic mean (average) is calculated by adding all the numbers in the dataset and dividing by the total count of numbers.
$$Average = \frac{\text{Sum of all observations}}{\text{Total number of observations}}$$
### Step-by-Step Solution
* **Calculation:** Add the five given numbers together.
Sum = $205 + 302 + 108 + 403 + 202$
Sum = $1220$
* **Calculation:** Count the number of observations. There are 5 numbers.
* **Calculation:** Divide the sum by the count.
Average = $\frac{1220}{5}$
Average = $244$
### Exam Strategy & Shortcut
**Assumed Mean Method:**
Pick a convenient number close to the values, say 200. Let's find the deviations from 200:
205 $\rightarrow +5$
302 $\rightarrow +102$
108 $\rightarrow -92$
403 $\rightarrow +203$
202 $\rightarrow +2$
Sum of deviations = $5 + 102 - 92 + 203 + 2 = 220$.
Average of deviations = $\frac{220}{5} = 44$.
Final Average = Assumed Mean + Average of deviations = $200 + 44 = 244$.
This method prevents dealing with large sums and reduces arithmetic errors.
### Common Pitfall
A common trap in multiple-choice questions is presenting the "Sum" as one of the options. Notice that 1220 is option (d). Students who calculate the sum but forget to divide by $N$ will prematurely select (d) and lose marks. Always complete the final division step.
### Final Answer
**Therefore, the correct answer is 244.**