C) (0.85 + x/100)(250+145) does not give the correct answer.
Explanation
A) works; adding the two costs together is 250+145=395. We multiply this by 0.85 because 100%-15%=85%=0.85. We also have x% tax, which is represented by x/100, added to 100% of the value, or 1.00. Altogether this gives us
395(0.85)(1+x/100) = 395(0.85 + (0.85x/100)) = 395(0.85) + 395(0.85x/100)
= 395(0.85) + 395(0.0085x)
B) works; we have 250+145 for the original price; we have 85% = 0.85 of the value; we also have 100% + x%, which is (100+x)/100.
C) does not work; (0.85+x/100)(395) does not take into consideration that you are finding the tax after taking the 85%. This will simplify out to
0.85*395 + (x/100)(395) = 335.75 + 395x/100 = 335.75 + 3.95x, which is too much.
D) works; simplifying the expression from A, we have 395(0.85) + 395(0.0085x) = 335.75 + 3.3575x.
Answer:
(b) 0.251
Step-by-step explanation:
1. Standard deviation equation:

Where X is the mean of the data, and N the amount of data. Then, N=5
2. Estimate the Mean:

3. Caclulate Standard deviation:


Answer:
281 ft^2
Step-by-step explanation:
We need to add each individual 2d shape together to find the surface area
Bottom: 5*12 = 60
Left side and right side: 4*5 = 20, 2 sides so 20*2= 40
Side facing us and side facing away from us: 12*4 = 48, 2 sides so 48*2=96
Top side that is cut by base of triangle: 7*5 = 35
Each triangle face: base = 5 (12-7), height = 5 1/2base * height so each triangle is .5*5*5 = 12.5; 4 triangles so 12.5*4=50
60+40+96+35+50=281