Answer:
852 students walking to school
Step-by-step explanation:
Lets start with a simple example so you can get it
if 60% of 100 students walk to school that means
60 students walk to school... right??
so lets simplify it more that means you have multiplied 100 (students) by 60%
or
(note: you can say that 60% is equal to
)
so the problem told 60% of 1420 students walk to school that means we should
do this: 
A+5=5a+5 Subtract a from each side
5=5a+5 Subtract 5 from each side
0=5a Divide each side by the number before the variable to get it alone.
--- ---
5 5
a=0

Not much more to say about this. Just multiply the integer by the coefficient.
ANSWER
Period: 2π , amplitude: 4
EXPLANATION
The graphed function is

The amplitude of this function is

The period is 2π because there is no phase shift hence the period is still equal to the parent function.
Period: 2π , amplitude: 4