Chained division with small decimals: Evaluate 99.999 ÷ 0.99 ÷ 0.00991234 and select the closest option.
Correct Answer: 10000
Introduction / Context:A chained division by decimals is equivalent to multiplying by their reciprocals. Dividing by a number just under 1 increases the value slightly, and dividing by a very small number (around 0.01) increases it by around two orders of magnitude, guiding us toward the right scale of the answer.
Given Data / Assumptions:
- a = 99.999
- b = 0.99
- c = 0.00991234
Concept / Approach:Compute sequentially: (99.999 / 0.99) ≈ 101.0, then divide that by c ≈ 0.0099, which is close to multiplying by ~101. The magnitude suggests a result near ten thousand. Choose the closest option accordingly.
Step-by-Step Solution:
Step 1: 99.999 / 0.99 ≈ 101.0Step 2: 101.0 / 0.00991234 ≈ 101.0 * (≈100.88) ≈ 10200 (ballpark)Exact calculation is about 10190Verification / Alternative check:Back-of-the-envelope: 100 / (0.01) = 10000, and our inputs are slightly adjusted from these round anchors, so ~10,000 is very reasonable. The nearest option is 10,000.
Why Other Options Are Wrong:
- 100, 1000: too small by orders of magnitude.
- 100000: too large by about a factor of 10.
- 12000: closer than others but still farther than 10000 from the true ≈10190 when considering the coarse options.
Common Pitfalls:Assuming that dividing by 0.99 reduces the value (it actually increases it), or mishandling decimal places in the tiny divisor 0.0099....
Final Answer:10000