Answer:
The equation can be used to determine the amount of money S(t) that her savings account has after t years is 
Step-by-step explanation:
A student invests $500 in a savings account
Principal = $500
Rate of interest = 4% = 0.04
We are supposed to find equation can be used to determine the amount of money S(t) that her savings account has after t years
Formula : 
Where A is the amount after t years =S(t)
t = time
r = rate of interest in decimals =0.04
P = Principal=500
Substitute the value in the formula :
So, 

Hence The equation can be used to determine the amount of money S(t) that her savings account has after t years is 
The answer is 23.2 I just entered the data into an online standard deviation calculator.
Answer:
a 0
b) 0.9
c) 0.85
d) 0.25
e) 0.1
f) 0.0375
Step-by-step explanation:
a)
As A and B are two disjoints events, then P(A and B) is
P(A and B)=0
b)
As A and B are two disjoints events, then P(A or B) is
P(A or B)=P(A)+P(B)
P(A or B)=0.15+0.75=0.9
c)
P(not A)=1-P(A)
P(not A)=1-0.15=0.85
d)
P(not B)=1-P(B)
P(not B)=1-0.75=0.25
e)
P(not (A or B))=1-P(A or B)
P(not (A or B))=1-0.9=0.1
f)
P(A and (not B))=P(A)*P(not B)
P(A and (not B))=0.15*0.25=0.0375
Answer:
I think its -2/5 but not sure
Step-by-step explanation:
The unit rate would be 11/2. Hope this helped.