a. What percent of people earn less than $40000?
Solution: Let S be the random variable of a salary of employee (in $), S ~ N(50000,20000). Then the random
variable X =−50000
20000
~N(0,1).
( < 40000) = ( <
40000 − 50000
20000 ) = ( < −0.5) = (−0.5) = 0.3085375.
Here Φ(x) denotes the cumulative distribution function of a standard normal distribution.
Answer: 31%.
b. What percent of people earn between $45000 and $65000?
Solution:
(45000 < < 65000) = (
45000 − 50000
20000 < <
65000 − 50000
20000 ) = (−0.25 < < 0.75)
= (0.75) − (−0.25) = 0.7733726 − 0.4012937 = 0.3720789.
Answer: 37%.
c. What percent of people earn more than $70000?
Solution:
( > 70000) = ( >
70000 − 50000
20000 ) = ( > 1) = 0.8413447.
Answer: 84%.
Answer:
A, C & D
Step-by-step explanation:
A) 1 + 3x = -x + 4 {subtract 1}
1 + 3x -1 = -x + 4 - 1
3x = -x + 3 {add x}
3x + x = -x + 3 + x
4x = 3 {Divide by 4}
4x/x = 3/4
x = 3/4
C) 1 + 3x = -x +4 {Add x}
1+ 3x + x = - x +4 + x
1 + 4x = 4 {subtract 1}
4x = 4 - 1
4x = 3 {Divide by 4}
D) 1 + 3x = -x + 4 { Subtract 3x}
1 = -x + 4 -3x
1 = -4x + 4 Subtract 4}
1 - 4 = -4x
-3 = -4x {Divide by -4}
-3/-4 = x
x = 3/4
x = 3/4
Answer:
-3p-40
Step-by-step explanation:
-(7p+6)-2(-1-2p)
-7p-42+2+4p
-3p-40
