Hi please help me really need it!
1 answer:
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Answer:
We have to add 1.86 L of water to make the solution 7% saline.
Step-by-step explanation:
The concentration of a saline solution is given by
C(x) =
where x represents the amount of water used to dilute the solution.
We have to find how much water must be added to obtain a solution that is 7% saline.
If we see the equation we notice that as we add the value of x, the concentration of the solution decreases.
Here C(x) = 0.07
0.07 =
Rearranging,
1 + x =
1 + x = 2.86
x = 1.86 L
We have to add 1.86 L of water to make the solution 7% saline.
Answer:
x = 10
Step-by-step explanation:
Given
+ 13 =
( multiply through by 10, the LCM of 5 and 2 to clear the fractions )
2x + 130 = 15x ( subtract 2x from both sides )
130 = 13x ( divide both sides by 13 )
10 = x
Answer:
1.86 < t < 2.31
Step-by-step explanation:
State the null and alternative hypotheses.
We need to conduct a hypothesis in order to check if the mean height actually is higher\lower than an specified value, the system of hypothesis would be:
Null hypothesis:
Alternative hypothesis:
Or like this:
Null hypothesis:
Alternative hypothesis:
If we analyze the size for the sample is < 30 and we don't know the population deviation so is better apply a t test to compare the actual mean to the reference value, and the statistic is given by:
(1)
t-test: "Is used to compare group means. Is one of the most common tests and is used to determine if the mean is (higher, less or not equal) to an specified value".
Calculate the statistic
We don't know on this case the calculated value and with the p value we can find it.
P-value
The first step is calculate the degrees of freedom, on this case:
Since is a one side test the p value would be:
And we can find the critical value with the following excel code:
"
=T.INV(1-0.035,8)" and we got
And cannot be a lower tail test since all the options have positive values for the statistic. So on this case the best option is:
1.86 < t < 2.31