Question

1. Drew ran the first 2 3/4 miles of a 5-mile race in 1/2 hour. What was his average rate, in miles per hour, for this first part of the race? Describe how you solved the problem.

Answer 1

5 1/2

Explanation:

Rate x Time = Distance. If you know 2 of the parts, you can figure out the 3rd part. You know the time and the distance, so plug those in and solve.

Let R = rate

R(1/2) = 2 3/4 Let's change 2 3/4 into a improper fraction.

R(1/2) = 11/4 Multiply 4x2 and then add 3 that gets you 11 and the bottom number stays the same. Next, multiply both sides of the equation by 2.

R = 22/4 or 11/2 or 5 1/2 miles per hour.