Answer:
x = ±5
Step-by-step explanation:
x² - 25 = 0
x² = 25
√x² = √25
x = ±5
Check:
5² - 25 = 0
-5² - 25 = 0
25 - 25 = 0
Answer:
30 CDs and 10 Videos were sold.
Step-by-step explanation:
Given that a used book store also started selling used CDs and videos. In the first week, the store sold 40 used CDs and videos, at 4.00 per CD and 6.00 per video.
The sales for both CDs and videos totaled to 180.00.
Let CDs be x and Videos be y
Then we have x+y =3040
and 4x+6y = 180
Two simultaneous equations in two variables and can be solved by elimination method
multiply I equation by 4 and subtract from II.
2y = 20
y =10
x = 30
30 CDs and 10 Videos were sold.
Answer:
Step-by-step explanation:
Hello!
So you have a new type of shoe that lasts presumably longer than the ones that are on the market. So your study variable is:
X: "Lifetime of one shoe pair of the new model"
Applying CLT:
X[bar]≈N(μ;σ²/n)
Known values:
n= 30 shoe pairs
x[bar]: 17 months
S= 5.5 months
Since you have to prove whether the new shoes last more or less than the old ones your statistical hypothesis are:
H₀:μ=15
H₁:μ≠15
The significance level for the test is given: α: 0.05
Your critical region will be two-tailed:


So you'll reject the null Hypothesis if your calculated value is ≤-1.96 or if it is ≥1.96
Now you calculate your observed Z-value
Z=<u>x[bar]-μ</u> ⇒ Z=<u> 17-15 </u> = 1.99
σ/√n 5.5/√30
Since this value is greater than the right critical value, i.e. Zobs(1.99)>1.96 you reject the null Hypothesis. So the average durability of the new shoe model is different than 15 months.
I hope you have a SUPER day!
Answer: I assume this ques was formatted like this originally. 4/10 = 2. If so the answer is 5 making the second fraction 2/5. Let me know if this is not the case. Hope this helps!
Answer:
0
Step-by-step explanation:
54m² - 54m² = 0
Water is 0