Solve a Formula for a Specific Variable: example 2.58

Jamal rides his bike at a uniform rate of 12 miles per hour for $3 \frac{1}{2}$ hours. What distance has he traveled?

Work it out on paper first. Then open the solution one step at a time, and stop as soon as you can finish on your own.

Your turn

The book's Try It right after this example: same idea, new numbers. Only the answer is given.

Lindsay drove for $5 \frac{1}{2}$ hours at 60 miles per hour. How much distance did she travel?

How did it go?

Step 1. Read the problem.
Step 2. Identify what you are looking for.		distance traveled
Step 3. Name. Choose a variable to represent it.		Let d = distance.
Step 4. Translate: Write the appropriate formula.		$d = r t$

Substitute in the given information.		$d = 12 \cdot 3 \frac{1}{2}$
Step 5. Solve the equation.		$d = 42$ miles
Step 6. Check
Does 42 miles make sense?
Jamal rides:

Step 7. Answer the question with a complete sentence.		Jamal rode 42 miles.

Step 1. Read the problem.
Step 2. Identify what you are looking for.		distance traveled
Step 3. Name. Choose a variable to represent it.		Let d = distance.
Step 4. Translate: Write the appropriate formula.		$d = r t$

Substitute in the given information.		$d = 12 \cdot 3 \frac{1}{2}$
Step 5. Solve the equation.		$d = 42$ miles
Step 6. Check
Does 42 miles make sense?
Jamal rides:

Step 7. Answer the question with a complete sentence.		Jamal rode 42 miles.