How many feet are equivalent to 34text{ yards}? (1text{ yard} = 3text{ feet})
GMAT Problem-Solving and Data Analysis : (PS_DA) Questions
How many feet are equivalent to \(34\text{ yards}\)? (\(1\text{ yard} = 3\text{ feet}\))
1. TRANSLATE the problem information
- Given information:
- \(\mathrm{34~yards}\) need to be converted to feet
- Conversion factor: \(\mathrm{1~yard = 3~feet}\)
- What we need to find: The number of feet equivalent to \(\mathrm{34~yards}\)
2. INFER the conversion approach
- Since we're converting from larger units (yards) to smaller units (feet), we need more of the smaller units
- This means we multiply: \(\mathrm{34~yards × 3~feet~per~yard}\)
- The conversion factor \(\mathrm{\frac{3~feet}{1~yard}}\) ensures the yards cancel out, leaving only feet
3. SIMPLIFY the calculation
- \(\mathrm{34~yards × \frac{3~feet}{1~yard}}\)
\(\mathrm{= 34 × 3~feet}\)
\(\mathrm{= 102~feet}\)
Answer: \(\mathrm{102}\)
Why Students Usually Falter on This Problem
Most Common Error Path:
Weak INFER skill: Students confuse the direction of conversion and divide instead of multiply.
They might think: "There are 3 feet in 1 yard, so 34 yards must be \(\mathrm{34 ÷ 3 = 11.33~feet}\)." This backwards reasoning comes from not recognizing that converting to smaller units requires more of those units, not fewer. This leads to an incorrect answer of approximately \(\mathrm{11}\).
Second Most Common Error:
Poor SIMPLIFY execution: Students set up the problem correctly but make arithmetic errors.
They correctly identify that \(\mathrm{34 × 3}\) is needed, but miscalculate and get \(\mathrm{92, 112}\), or other incorrect products. Simple multiplication errors can derail an otherwise correct approach.
The Bottom Line:
The key insight is recognizing which direction the conversion goes - when converting from larger to smaller units, you get more units, so you multiply. This unit conversion logic is what separates confident problem-solvers from students who guess at whether to multiply or divide.