What causes /pages/ to appear in URI?
As it turned out, you had a parent page with slug pages.
How to remove it?
Don’t have a parent page.
is there an easy way to prevent child pages from showing the parent
page in the URI?
This has been asked and answered countless times, for example here, you can find more here. Im not going to duplicate these answers.
Parent and child page relationship isn’t just a tool for editor or developer to organize their pages in admin area. URI and page relationships design should be a part of your development process. Pages should be organized meaningfully. If child and parent relationship between two pages doesn’t make sense, just remove the relationship.
Good URI should function as a breadcrumb. User should know exactly where he/she is.
While this isn’t always the case, note that parent page should ideally have a logical list of all it’s children.
Example:
You have 4 pages: faq, rules, terms, instructions
While you could use all of these individually, it would make a perfect sense to make a parent page info which contains a pretty list to all these pages. Now you don’t have to have trillion links in your menu or a single big page which makes users flee as soon as he/she sees it. You have a single Info which contains links to logically isolated subjects – easy for eyes and easy to reason about.
In your case www.site.com/our-company/contact-us/ would make sense if you have other pages too, e.g www.site.com/our-company/about-us/ but if it was a single child, I would remove the parent.