First convert the distance she ran from a mixed number to a improper fraction:
• 4-1/2 equals 9/2.
Since this a unit rate problem divide the km by the time traveled.
• 9/2 (km) ÷ 3/4 (hour). When you divide a number by a fraction use (Keep-Change-Flip).
• 9/2 × 4/3 = 36/6 miles/hour.
That's means 36/6 = 18/3 = 6 km/ hour.