Multiple choice

Julia and Cescca are invited for a party. Julia leaves home in car at 9:05 am, driving at an average speed of $10$ miles per hour. After $15$ minutes , Cessca leaves in a car at an average speed of $25$ miles per hour.At what time Cescca catch up to her?

  1. $9:15$AM
  2. $9:20$AM
  3. $9:26$AM
  4. $9:30$AM
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Julia travels for 15 minutes at 10 mph, covering 2.5 miles. Cessca catches up at a relative speed of 25-10 = 15 mph. Time taken = 2.5/15 hours = 1/6 hours = 10 minutes. Cessca leaves at 9:20, so she catches up at 9:30.

AI explanation

By 9:20 AM, Julia has traveled for 15 minutes at 10 mph, giving her a head start of 10 * (15/60) = 2.5 miles. Cessca leaves at 9:20 AM and travels at 25 mph, creating a relative speed of 25 - 10 = 15 mph between them. The time it takes Cessca to close the 2.5-mile gap is found by dividing the distance by the relative speed: 2.5 / 15 = 1/6 of an hour, which equals 10 minutes. Adding 10 minutes to Cessca's 9:20 AM departure time results in 9:30 AM.

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