3x - 15 = 39
+ 15 +15
3x = 54 (divide by 3 on each side)
X = 18
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:
30cm3
Step-by-step explanation:
Volume=Base area *height
Base area is a triangle=1/2 *base*height
1/2*3*4=6cm2
Height=5cm
Volume=6*5=30cm3
Answer:
Total possible number of outcomes = C(24,6) [24 choose 6]
=24!/(6!18!)
= 134596
Out of which there is only one winning combination.
Therefore we conclude:
P(win 20000)=1/134596
P(lose 1)=134595/134596
and hence the expected value is:
20000*(1/134596)+(-1)*(134595/134596)
=-114595/134596
=-0.8514 (rounded to four places after decimal)
Step-by-step explanation:
Hope this helped!
