#### Answer

90 seconds

#### Work Step by Step

Step 1: The combined total distance the jogger ran is:
300 + 450 + 600, or 1350 meters.
Step 2: Divide 1350 by 15 (The jogger runs 15 meters per second)
$\frac{1350}{15}$ = 90
Step 3: The jogger ran the total race in 90 seconds.