Let's solve this problem step-by-step.

Problem:

The width of a 2-by-4 piece of wood is given as $3 \frac{1}{2}$ inches. We need to find the total width of 28 such 2-by-4s laid side-by-side.

Step 1: Convert the Mixed Number to an Improper Fraction

The given width is $3 \frac{1}{2}$ inches. Converting this to an improper fraction: $3 \frac{1}{2} = \frac{3 \times 2 + 1}{2} = \frac{7}{2} \text{ inches}$

Step 2: Calculate the Total Width

If 28 pieces are laid side-by-side, the total width is: $\text{Total width} = 28 \times \frac{7}{2}$

Simplifying: $\text{Total width} = \frac{28 \times 7}{2} = \frac{196}{2} = 98 \text{ inches}$

Step 3: Final Answer

The correct answer is: $\boxed{98 \text{ inches}}$

Let me know if you'd like further details or have any questions!

Related Questions:

1. How would the total width change if the number of 2-by-4s increased to 35?
2. What would be the total width if the width of each piece was $4 \frac{1}{4}$ inches instead?
3. How do you convert a mixed number to an improper fraction?
4. If the width of each piece was given in centimeters, how would you convert it to inches?
5. What is the formula for finding the total width when given a number of pieces and the width of each piece?

Tip:

When working with mixed numbers, always convert them to improper fractions before performing multiplication or division for accurate calculations.