Step-by-step explanation:
The T-shirt is launched with an initial upward velocity of 60 ft/s from a height of 5 feet. Its equation of motion is given by :
....(1)
(a) For maximum height, put 
So,

Now put,

So, the time taken for the T-shirt to reach maximum height is 2.5 seconds.
(b) Put x = 2.5 s in equation (1)
4^-5=1/1024 or 2/2048 or 3/3072
1/3m +3 - 5/6m= -15
I am going to change the first fraction to match the second fraction
2/6m +3 - 5/6m= -15
Simplify by subtracting 5/6m from 2/6m
-3/6m +3 = -15
Subtract 3 from each side
-3/6m = -18
Take the minus signs off
3/6m = 18
Simplify
1/2m = 18
Divide by 1/2 on each side
m= 18 ÷ 1/2= 36
Option D, m is 36
Hope this helped