1,400 is 1,432 rounded to the nearest 100! :)
Answer: 7/3
Step-by-step explanation:
21/9
7/3 is the fraction in simplest form
The answer is currently A so yep thats the answer ok
When the ball hits the ground, the height is 0.
0 = 100 - 16t²
0 = (10 - 4t)(10 + 4t)
0 = 10 - 4t or 0 = 10 + 4t
4t = 10 or -4t = 10
t =
or t = 
Time cannot be negative (unless you have a time machine) so disregard 
Answer: t =
= 2.5 seconds