How much time does it take by shuttle bus from the terracotta warriors to the mausoleum (and how frequent are the buses)?

I am thinking of taking tourist bus 5 to go to terracotta, visit for 3 hours, then take the free shuttle you mention to the mausoleum.

Also, to go back to Xi'an, can I catch the tourist bus 5 from the mausoleum, or do I have to take the shuttle back to the terracotta warriors and then catch the bus back to Xi'an?

Thank you in advance for your help.