feasibility of doing 2 summer internships

I've been fortunate enough to get a fixed income internship this summer, but it's fairly short and only 5 weeks. The expected workload is 20-30hrs per week though I've heard from previous interns from my school that it will take less time. It is less of an internship where we're expected to do real hands on things and more so like they give us a project to work on for our sake and give a presentation on it. During spring when I was applying everywhere, there was also a middle market PE firm that I interviewed for but they didn't officially get back to me. Just today, one of the associates emailed me essentially asking if I was still looking for a summer opportunity.

Is it reasonable for me to say that I am? If I do say that I'm looking for an opportunity, should I leave out that I have another internship? (scared might not get it if I already have something else). If I do include that I have another internship, I intend on saying that it is lower commitment, I can manage both, and I still want to take the opportunity. To clarify, this PE opportunity will likely be more involved in the actual deal process.