This is a proportion problem.
z 4
--- = ----
12 5
We can cross multiply and divide.
5z = 48
z = 9.6
Hope this helps!
Number of weekend minutes used: x
Number of weekday minutes used: y
This month Nick was billed for 643 minutes:
(1) x+y=643
The charge for these minutes was $35.44
Telephone company charges $0.04 per minute for weekend calls (x)
and $0.08 per minute for calls made on weekdays (y)
(2) 0.04x+0.08y=35.44
We have a system of 2 equations and 2 unkowns:
(1) x+y=643
(2) 0.04x+0.08y=35.44
Using the method of substitution
Isolating x from the first equation:
(1) x+y-y=643-y
(3) x=643-y
Replacing x by 643-y in the second equation
(2) 0.04x+0.08y=35.44
0.04(643-y)+0.08y=35.44
25.72-0.04y+0.08y=35.44
0.04y+25.72=35.44
Solving for y:
0.04y+25.72-25.72=35.44-25.72
0.04y=9.72
Dividing both sides of the equation by 0.04:
0.04y/0.04=9.72/0.04
y=243
Replacing y by 243 in the equation (3)
(3) x=643-y
x=643-243
x=400
Answers:
The number of weekends minutes used was 400
The number of weekdays minutes used was 243
Mass = 100 g
Volume = 50 cm³
Density :
D = m / V
D = 100 / 50
D = 2 g/cm³
answer A
hope this helps!.
Answer: Using the information of the conditional relative frequency table, 123 students in the survey said that math was their favorite subject.
Solution:
1. The survey was given to 120 male students.
Acconding with the table, the proportion of male students with Math as favorite subject is 0.35. The quantity of male students with Math as favorite subject would be:
0.35(120)=42 male students
2. The survey was given to 180 female students.
Acconding with the table, the proportion of female students with Math as favorite subject is 0.45. The quantity of female students with Math as favorite subject would be:
0.45(180)=81 female students
Then the total of students in the survey said that math was their favorite subject would be:
42 male students + 81 female students = 123 students
Answer:
First derivative the equation
39x²-318x-412=0
then use the quadratic formula
then x = 9.29 or x = -1.14