Answer: D) 
Step-by-step explanation:
Based on the provided information, we have
Sample size: n= 15
sample mean: 
Sample standard deviation: s= $20
Since the population standard deviation is not known, we utilize a t-test.
For a significance level of 95% confidence: 
Critical t-value : 
[Using the Student's t-value table]
The required 95% confidence interval yields:-
Thus, the sought-after 95% confidence interval for the mean amount spent by credit card customers during their initial visit to the new store in the mall, assuming normal distribution of the spending amounts, is:
In a semicircle, there exist pi radians, whereas a full circle consists of 2pi radians. Since 2pi equals approximately 2*3.14, it results in roughly 6.28 radians in half a circle. The total of 2pi radians corresponds to 360 degrees.
Examining Talia's steps to derive the line equation, we identify the erroneous step as detailed below:
Step 1:
Select a point on the line, such as (2,5)
Step 2:
<span>Select another point on the line, such as (1, 3)
Step 3:
</span><span>Measure units to find the slope. The line moves 1 unit to the right and 2 units upward, resulting in a slope of
(5-3)/(2-1) = 2/1 = 2
Step 4:
</span><span>Apply these values in the point-slope form
y - y1 = m(x - x1)
y - 3 = 2(x - 1)
y = 2x + 1
Hence, the conclusion is:
</span><span>Step 4 is erroneous due to incorrect application of (1, 3) in the point-slope format.</span>
Answer:
£170,000
Step-by-step explanation:
En 2010, Rafik adquirió una casa. Supongamos que el precio de compra fue $x. En 2015, Rafik vendió la casa a Bianca obteniendo un 20% de ganancia. Esto se traduce en 20% de x lo que equivale a 0.2 × x = 0.2x. Por tanto, Rafik vendió la casa a Bianca por x + 0.2x = 1.2x. Bianca compró la casa a 1.2x.
La casa fue vendida por Bianca en 2019 con una pérdida del 5%. Esto implica que el 5% de pérdida equivale a 0.05(1.2x) = 0.06x.
Por consiguiente, la venta de la casa por Bianca se realizó a 1.2x - 0.06x = 1.14x. Dado que la casa se vendió por £193,800.
⇒ 1.14x = 193,800
x = 193,800/1.14
x = £170,000
Rafik pagó £170,000 por la casa en 2010.
Answer:
1. 8.4 2. 15
Step-by-step explanation:
1. 4x + 8y = 40
when y = 0.8
4x + 8 × 0.8 = 40
4x = 40 - 8 × 0.8
4x = 40 - 6.4 = 33.6
....x = 33.6 / 4 = 8.4
2. 3a + b = 54
when b = 9
3a + 9 = 54
3a = 54 - 9
3a = 45
.....a = 45 / 3 = 15
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