In the second one I'm pretty sure you just measure the length of the points.
Answer:
A prime numbers are numbers which have only two factor
Answer:
The graph of the function 
is attached as image below.
Analysis:
We have two intersection points in the graph
The function intersects the y-axis at points (0,4)
The function intersects the x-axis at points (-16,0)
f(x) is positive for x>-`16
f(x) is negative for x<-`16
Y = 1.25x + 30 <== ur function
for 3 hrs.....x = 3
y = 1.25(3) + 30
y = 3.75 + 30
y = 33.75 <=== for 3 hrs
800/6=x/16 6x=12800 divide and get 2133 1/3
