JAMB 2017 Mathematics · Question 14

Find the range of the following set of numbers 0.4, −0.4, 0.3, 0.47, −0.53, 0.2 and −0.2

Options

  1. A.1.03
  2. B.0.07
  3. C.0.03
  4. D.1.0

Answer: D. 1.0

Explanation written with AI and checked against the answer key

Analysis

To find the range of a set of numbers, you must identify the difference between the highest value (maximum) and the lowest value (minimum) in the data set.

Formula:

Range=Highest Value−Lowest Value\text{Range} = \text{Highest Value} - \text{Lowest Value}
Step-by-Step Solution

Step 1: List the numbers and identify the maximum and minimum values. The given set is: 0.4,−0.4,0.3,0.47,−0.53,0.2,−0.20.4, -0.4, 0.3, 0.47, -0.53, 0.2, -0.2

  • Positive numbers: 0.4,0.3,0.47,0.20.4, 0.3, 0.47, 0.2
  • Negative numbers: −0.4,−0.53,−0.2-0.4, -0.53, -0.2

Comparing the positive numbers, the largest is 0.470.47. Comparing the negative numbers, the smallest (the one furthest to the left on the number line) is −0.53-0.53.

Step 2: Apply the range formula.

Range=0.47−(−0.53)\text{Range} = 0.47 - (-0.53)

Step 3: Perform the calculation. When you subtract a negative number, it becomes addition:

Range=0.47+0.53\text{Range} = 0.47 + 0.53
Range=1.00\text{Range} = 1.00
Conclusion

The range of the set is 1.01.0. Comparing this to your options: A. 1.03 B. 0.07 C. 0.03 D. 1.0

The correct option is D.

Exam Tip

Always be careful with signs when dealing with negative numbers! A common mistake is to simply subtract the absolute values (e.g., 0.47−0.530.47 - 0.53). Remember that subtracting a negative is the same as adding the positive equivalent. Always visualize the number line if you are unsure which number is "smaller."

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