5x + 10y = 50
x + y = 8
x = 8 - y
5*(8-y) + 10y = 50
40 - 5y + 10y = 50
10y - 5y = 50 - 40
5y = 10
y = 2
x + y = 8
x + 2 = 8
x = 8 - 2
x = 6
She has 6 nickels and 2 dimes
Answer:
"Because the particles (electrons and ions) in a plasma have an electrical charge, the motions and behaviors of plasmas are affected by electrical and magnetic fields. ... Ions have a positive electrical charge because they have more positively charged protons than negatively charged electrons."
-Educationscied.ucar.edu › plasma
Answer:
5
Step-by-step explanation:
15 ×
= 5
Answer:
2000
Step-by-step explanation:
S.I=P×rate / 100×time
30000×8 / 100×5/6
=2000
Answer:
A sample of 997 is needed.
Step-by-step explanation:
In a sample with a number n of people surveyed with a probability of a success of
, and a confidence level of
, we have the following confidence interval of proportions.
In which
z is the z-score that has a p-value of
.
The margin of error is of:

A previous study indicates that the proportion of left-handed golfers is 8%.
This means that 
98% confidence level
So
, z is the value of Z that has a p-value of
, so
.
How large a sample is needed in order to be 98% confident that the sample proportion will not differ from the true proportion by more than 2%?
This is n for which M = 0.02. So






Rounding up:
A sample of 997 is needed.