The weight of an object on Venus is approximately 9/10 of its weight on Earth. The weight of an object...

1. TRANSLATE the problem information

• Given information:
  • Weight on Venus = \(\frac{9}{10}\) of Earth weight
  • Weight on Jupiter = \(\frac{23}{10}\) of Earth weight
  • Earth weight = 100 pounds
  • Find: How many MORE pounds on Jupiter than Venus
• This tells us we need to calculate both planetary weights, then compare them.

2. INFER the solution approach

• The key word "more" indicates we need a difference calculation
• Strategy: Calculate each planetary weight first, then subtract to find the difference

3. SIMPLIFY to find Venus weight

• Venus weight = \(\frac{9}{10} \times 100\) pounds = 90 pounds

4. SIMPLIFY to find Jupiter weight

• Jupiter weight = \(\frac{23}{10} \times 100\) pounds = 230 pounds

5. SIMPLIFY to find the difference

• Difference = Jupiter weight - Venus weight = \(230 - 90 = 140\) pounds

Answer: C. 140

Why Students Usually Falter on This Problem

Most Common Error Path:

Weak INFER skill: Students correctly calculate individual planetary weights but fail to recognize that the question asks for a comparison ("how many more"). They stop after finding one weight value.

This may lead them to select Choice A (90) if they calculated Venus weight, or Choice D (230) if they calculated Jupiter weight.

Second Most Common Error:

Poor TRANSLATE reasoning: Students misinterpret the problem setup, thinking the 100 pounds is the weight on Venus rather than Earth, then try to work backwards to find Earth weight.

If they calculate \(100 \div \frac{9}{10} = 100 \times \frac{10}{9} \approx 111\), this may lead them to select Choice B (111).

The Bottom Line:

This problem tests whether students can move beyond individual calculations to perform the comparison that answers the actual question. The word "more" is the critical signal that a difference calculation is needed.