Please help me with problem 3 letters a and b too

Answer:
a) 30
b) 2
at 2 seconds, the balloon reaches the greatest height, 30
Step-by-step explanation:
y=height
x=seconds
The greatest height that the table shows is 30; the number of seconds it took to reach 30 is 2, (2,30)
Accordingly:
at 2 seconds, the balloon reaches the greatest height, 30
Pls let me know if this helps!