Answer:
13
Step-by-step explanation:
there is a rule that says that if you add any 2 sides, it should be more than the third. 9+21 is greater than 13. 21+13 is greater than 9. 13 is the only number which if you add 9 to it it will be greater than 21. 12 will equal 21, but it still wont work.
hope this helps :))
Answer:
5.714 liters of the 5% solution and 4.286 of the 40%.
Step-by-step explanation:
Let x be the volume of 40% solution and y = volume of the 5% solution.
x + y = 10
0.40x + 0.05y = 0.20(x + y)
From the first equation x = 10 -y so we have:
0.40(10 - y) + 0.05y = 0.20( 10 - y + y)
4 - 0.40y + 0.05y = 2
-0.35y = -2
y = 5.714 liters of the 5%.
and x = 10 - 5.714 = 4.286 liters of the 40% solution.
Step-by-step explanation:
4500 + 1.20x < 4.80x
4500 < 4.80x - 1.20x
4500 < 3.60x
4500/3.60 < x
1250 < x.......minimum number would be 1251
Every confidence interval has associated z value. As confidence interval increases so do the z value associated with it.
The confidence interval can be calculated using following formula:

Where

is the mean value, z is the associated z value, s is the standard deviation and n is the number of samples.
We know that standard deviation is simply a square root of variance:

The confidence interval of 95% has associated z value of <span>1.960.
</span>Now we can calculate the confidence interval for our income: