Bracketed ratio near integers: Evaluate [137 ÷ 17 × 3.99] / [4.02 × 3.98] and choose the nearest option.
Correct Answer: 2
Introduction / Context:This expression compares two products of numbers close to integers. By recognizing near-cancellations and rounding sensibly, the result lands close to a small integer. This is typical in approximation questions where factors hover near 4 or 8, and divisions collapse to neat values.
Given Data / Assumptions:
- Numerator: (137/17) × 3.99
- Denominator: 4.02 × 3.98
Concept / Approach:Compute 137/17 exactly: that equals 8 + 1/17 ≈ 8.0588. Multiplying by ~3.99 is close to multiplying by 4 but slightly less. The denominator 4.02 × 3.98 is close to 4 × 4 = 16. The overall ratio should be near (8.06 × 4) / 16 ≈ 2.01, i.e., about 2.
Step-by-Step Solution:
137/17 ≈ 8.0588Numerator ≈ 8.0588 × 3.99 ≈ 32.14Denominator ≈ 4.02 × 3.98 ≈ 16.00Quotient ≈ 32.14 / 16.00 ≈ 2.01Verification / Alternative check:Exact computation yields about 2.0097, which is nearest to 2 among the listed choices. Thus, 2 is the correct selection.
Why Other Options Are Wrong:
- 2.5, 3.2, 3.5, 2.2: all lie farther from ≈2.01 and would overstate the ratio.
Common Pitfalls:Rounding 3.99 up to 4 while also rounding the denominator down (e.g., 4.02 → 4 and 3.98 → 4) without recognizing the near-compensating effects can skew the estimate.
Final Answer:2