The iron cube of side 42 com has a hole of diameter 14cm
1 answer:
Answer:
Step-by-step explanation:
Total surface of the cube = 6a²
= 6 * 42 * 42
= 10584 cm²
Hole that is drilled out, will make a cylinder shape in the middle of the cube
Volume of iron in the cube = Volume of cube - volume of cylinder
Volume of cube = a³
= 42 * 42 * 42
= 74088 cm³
Cylinder:
r = 14/2 = 7 cm
h = sideof the cube = 42 cm
Volume = πr²h
= 6468 cm³
Volume of iron in the cube = Volume of cube - volume of cylinder
= 74088 - 6468
= 67620 cm³
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Answer:
d. 200 and 2
Step-by-step explanation:
The Central Limit Theorem estabilishes that, for a normally distributed random variable X, with mean and standard deviation
, the sampling distribution of the sample means with size n can be approximated to a normal distribution with mean
and standard deviation
.
For a skewed variable, the Central Limit Theorem can also be applied, as long as n is at least 30.
In this problem, we have that:
Mean = 200
Standard deviation = 18
Sample size: 81
Standard error:
So the correct answer is:
d. 200 and 2