He drinks 8 glasses of water in one day. to know the number of glasses he drinks in 365 days, simply use cross multiplication as follows:
number of glasses per year = (365*8)/1 = 2920 glasses
so, yes his assumption is reasonable if he kept the same rate (8 glasses per day each day)
The answer would be A and C.
Hope this helps!<3
The answer is 15
these chords are congruent because the radius of the circle are perpendicular to the them
so we can find EF by making an equation:

so EF is = 3(15)+5=50
good luck