Answer:
Step-by-step explanation:
1) Let the random time variable, X = 45min; mean, ∪ = 30min; standard deviation, α = 15min
By comparing P(0 ≤ Z ≤ 30)
P(Z ≤ X - ∪/α) = P(Z ≤ 45 - 30/15) = P( Z ≤ 1)
Using Table
P(0 ≤ Z ≤ 1) = 0.3413
P(Z > 1) = (0.5 - 0.3413) = 0.1537
∴ P(Z > 45) = 0.1537
2) By compering (0 ≤ Z ≤ 15) ( that is 4:15pm)
P(Z ≤ 15 - 30/15) = P(Z ≤ -1)
Using Table
P(-1 ≤ Z ≤ 0) = 0.3413
P(Z < 1) = (0.5 - 0.3413) = 0.1587
∴ P(Z < 15) = 0.1587
3) By comparing P(0 ≤ Z ≤ 60) (that is for 5:00pm)
P(Z ≤ 60 - 30/15) = P(Z ≤ 2)
Using Table
P(0 ≤ Z ≤ 1) = 0.4772
P(Z > 1) = (0.5 - 0.4772) = 0.0228
∴ P(Z > 60) = 0.0228
Answer:
answer is 8
Step-by-step explanation:
2/3(x+7)=10
2x/3+14/3=10
2x/3=10-14/3==>30-14/3
2x/3=16/3
x=16/3*3/2
x=8
Answer:
x=2
Step-by-step explanation:
5x+
= 7
5x+4 =7 (2)
5x+4=14
5x=14-4
5x=10
= 
x=2
Solution: Estimated time for the work is 40 hour work week.
Estimated payment to 3 laborers working 40 hours at cost $14 per hour is:
$1680
Estimated payment to 6 masons working 40 hours at cost $24 per hour is:
$5760
Estimated cost of material = $3143
Contractor wishes to make a profit of $500
Therefore, the mathematical expression that will give the estimated cost of the job is:

The estimated total cost is:
Cost =$11083