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)
A common denominator for 1/4 and 5/6...
1/4 = 3/12
5/6 = 10/12
the common denominator (LCM) would be 12