It's a simultaneous equation:
Steps:
1.Number the equations..
a+b=77 -1
a-b=13 -2
2. Choose what variable you want to use. In this case I would use the "b". Since the signs in front of the "b's" are different, add the two equations together
a + b = 77
+ + +
a (-b) = 13
Which gives;
2a = 90
Then solve to find a:
2a=90
a= 90/2
a=45
3.Then plug the "a" value into any of the original equations to find the "b" value. I would use equation 1 since the all the variables are positive.
a + b = 77
(45) + b = 77
b=77-45
b=32
4.Solution
a=45
b=32
Answer:
A. 0.22
B. 0.18
C. 0.25
D. 0.244
Step-by-step explanation:
S = {51 to 100} = 50
The sample space S contains values from 51 to 100 which is a total of 50 different values.
A.
Probability of A (lies between the values of 90 to 100 = 11).
11/50 = 0.22
B.
For a student to fail the course, his course has to be less than 60 = from 51 to 59. A total of 9 values.
9/50 = 0.18
C.
For student to get c, (70 to 79) a total of 10 values: 10/50 = 0.20
P(student did not get C) = 1-0.20 = 0.80
To get B, ( 80 to 89)
10/50 = 0.20
Probability that a student who is known not to have a c grade has a b grade = 0.20/0.80 = 0.25
D.
Probability of passing lies between 60 to 100 = 41 scores
41/50 = 0.82
Probability of student who passed having a B = 0.20/0.82 = 0.244
Answer:
14.65
Step-by-step explanation:
You add 13 + 6 3/4 then subtract 5 1/10 from that and you have your answer.
