The first time I did Whitney I was carrying 47 pounds, but that was when I was a inexperienced backpacking noob (2015
) and thought I had to start with 3 liters of water and had all kinds of extra stuff.
Last year when I did Onion Valley to Whitney, I manged to get it down to 44 pounds (but then that was a planned 6-7 day trip).
Shorter 2-3 day hikes I've been able to get under 40 pounds. I think I managed 37 for a planned 3 day hike last year.
The biggest problem is the biggest weight items (tent, pad, sleeping bag, bear can) really don't change weight unless you buy new lighter weight equipment.
Minimizing the water you start with is also a good idea. the Whitney trail has plenty of water sources up to Trail Camp, so 1 to 1.5 liters would probably be fine to start. A full 3 liters is 7 pounds... yes, I weighed the full camelbak to find out.