The first one - about 1 hour.
Why - Half of 2 1/2 is 1 1/4, so 1 1/4 x 3 = 3 3/4, which is what she has left.
____________________________________________________
It will take her 5 hours in total.
Why - If she has 3 3/4 left, 1 1/4 goes into that 3 times, and then 2 more because she had already hiked 2 2/4 mile [ 1 1/4 x 2 = 2 2/4. ]. ( 3 + 2 = 5 ).
________________________________________________________
Glad i could help and good luck.
_________________________
_________________________
_________________________