20 cm³ of pure alcohol is added to 10 cm of a 10% alcohol solution to strengthen it to a 70% solution.
Let x represent the volume of pure alcohol (100%) in cm³ needed to be added. Hence:
x * 100% + 10 cm³ * 10% = 70% * (x + 10 cm³)
x * 1 + 10 * 0.1 = 0.7 * (x + 10)
x + 1 = 0.7x + 7
x - 0.7x = 7 - 1
0.3x = 6
x = 20 cm³
Therefore 20 cm³ of pure alcohol is added to 10 cm of a 10% alcohol solution to strengthen it to a 70% solution.
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Answer:
20 cm³
Step-by-step explanation:
Answer:
22.66% probability that the mean weight will exceed 3.81 ounces
Step-by-step explanation:
To solve this question, we have to understand the normal probability distribution and the central limit theorem.
Normal probability distribution:
Problems of normally distributed samples can be solved using the z-score formula.
In a set with mean and standard deviation , the zscore of a measure X is given by:
The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the pvalue, we get the probability that the value of the measure is greater than X.
Central limit theorem:
The Central Limit Theorem estabilishes that, for a random variable X, with mean and standard deviation , a large sample size can be approximated to a normal distribution with mean and standard deviation
In this problem, we have that:
What is the probability that the mean weight will exceed 3.81 ounces
This probability is 1 subtracted by the pvalue of Z when X = 3.81. So
By the Central Limit Theorem
has a pvalue of 0.7734
1 - 0.7734 = 0.2266
22.66% probability that the mean weight will exceed 3.81 ounces
Answer:
Correct answer is 0.2290
Step-by-step explanation:
Answer:
The probability is 0.36
Step-by-step explanation:
For calculated the probability that a cookie has chocolate chips or pecans, we need to divide the number of cookies that has chocolate chips or pecans between the total number of cookies.
So, the number of cookies that has chocolate chips or pecans is calculate as: A + B - C
Where A are the number of cookies that have chocolate chips, B are the number of cookies that have Pecans and C are the number of cookies that have both chocolate chips and pecans. Then, the number of cookies that has chocolate chips or pecans is:
10 + 14 - 6 = 18
Finally, the total number of cookies is 50 so the probability is:
Answer:
Step-by-step explanation:
Estimate 3√43
Using same formula, we'll estimate √43
Answer to the original question:
Answer:
15
Step-by-step explanation:
Answer:
The value of x is 28cm.
Step-by-step explanation:
Area of a trapezium = ½h(a + b)
240 = ½×12×(12 + x)
240 = 6(12 + x)
240 = 72 + 6 x
240 - 72 = 6x
168 = 6x
168/6 = x
28 = x
Answer:
D
Step-by-step explanation:
Answer:
184
Step-by-step explanation:
The prime numbers between 40 and 56 are 41, 43, 47, and 53.
Add the prime numbers.
41 + 43 + 47 + 53
= 184
Answer:
184
Step-by-step explanation:
Prime numbers between 40 and 56: 41, 43, 47, 53.
41+43+47+53=
84+47+53=
131+53=
184