Given:
Matt and Phoebe are joining a triathlon. The event includes running for 3,500 m, cycling for 3,500 m, and swimming for 1,500m
The total length will be the sum of the 3 races
We will convert from meters to kilometers
1 kilometer = 1000 meter
So, Divide the total sum by 1000 to get the answer in kilometers
So, the answer will be the total length = 8.5 kilometers