Jerry spent 2.5 h biking up Mount Lowe, rested at the top for 30 minutes and biked down in 1.5 h. How far did he bike if his rate of ascent was 3 km/h less than his rate of descent?

We can help on this site, but we don't do your work for you. Post your attempt and we will help you from there.

Here's a hint: remember that the distance up the mountain = the distance down the mountain, and that distance = velocity times time. Can you finish the problem from here?