Answer:
Step-by-step explanation:
The firm tests 75 parts, and finds that 0.25 of them are notusable
n = 75
x = 0.25 \times 75 = 18.75≈19
Confidence level = 95%
So, Z_\alpha at 95% = 1.96
Formula of confidence interval of one sample proportion:
Confidence interval
The value of x is 1.25 or 1 1/4
Explanation
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275x=500-125x
Move variable to the left side and change its sign
275x+125x=500
Collect the like terms
275x+125x=500 =====> 400x=500
Divide both sides of the equation by 400
400x/400=500 =======> x=5/4 which is the same as 1 1/4 or 1.25
Hope this helps : )
258 cubic inches
Since the boxes are kind of on their own—>
First box: 7*2*12 = 168
Second box: 5*2*9=90
168+90 = 258