Compute a mixed fraction–decimal combination: Evaluate 31/10 × 3/10 + 7/5 ÷ 20 and present the result in simplest form.

Difficulty: Easy

Correct Answer: 1

Explanation:


Introduction / Context:
This question blends two straightforward fractional operations followed by addition. Keeping everything in fraction form helps prevent decimal mistakes and makes simplification transparent and exact.


Given Data / Assumptions:

  • Compute product: 31/10 × 3/10.
  • Compute division: 7/5 ÷ 20 = 7/5 × 1/20.
  • Add the two results and simplify.


Concept / Approach:
Perform each operation separately, reduce when possible, then add using a common denominator. Because denominators align to 100 naturally, the addition becomes especially tidy here.


Step-by-Step Solution:
Product: 31/10 × 3/10 = 93/100.Division: 7/5 ÷ 20 = 7/5 × 1/20 = 7/100.Sum: 93/100 + 7/100 = 100/100 = 1.


Verification / Alternative check:
Convert to decimals: 31/10 = 3.1, 3/10 = 0.3 → product 0.93; 7/5 = 1.4, ÷ 20 = 0.07; 0.93 + 0.07 = 1.00.


Why Other Options Are Wrong:
0 and 100 contradict the balanced additions; 107/200 equals 0.535 and arises from wrong denominators; 7/10 = 0.7 misses the second addend.


Common Pitfalls:
Dividing by 20 incorrectly (confusing 1/20 with 20/1); mixing decimals and fractions midstream; failing to combine to a common denominator.


Final Answer:
1

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