Answer:
3x - y = 0; 2x - y = -5
Step-by-step explanation:
Let x be the present age of Hans and y be the present age of Grace,
Since, in present Grace is three times as old as Hans,
⇒ y = 3x
⇒ 3x - y = 0
Now, after 5 years,
The age of Hans = x + 5,
And, the age of Grace = y + 5
Also, in 5 years Grace will be twice as old as Hans is then,
⇒ y + 5 = 2 ( x + 5 )
⇒ y + 5 = 2x + 10
⇒ 2x - y = -5
Hence, the required system of linear equations is,
3x - y = 0; 2x - y = -5
Answer:

Step-by-step explanation:
Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".
The Z-score is "a numerical measurement used in statistics of a value's relationship to the mean (average) of a group of values, measured in terms of standard deviations from the mean".
The population proportion have the following distribution
And we can solve the problem using the z score on this case given by:

We are interested on this probability:

And we can use the z score formula, and we got this:


And we can find this probability like this:

Answer:
C.
Step-by-step explanation:
There are two numbers on a standard cube that are divisible by 3, 3 and 6. Which gives you the fraction 2/6 and can be reduced to 1/3
1y - 1/x = 1/60 = x*y =60 = x=60/y
3y - 2(60/y) = 6
3y^2-120=6y
3(y^2-40-2y) =0
y^2-40-2y=0
y = 7.4
3(7.4)-2x=6
22.2-2x = 6
2x = -16.2
x = -8.1
Given:
22
gallons of 16% ammonia
24%
ammonia
Find:
Number
of gallons of water to remove
Solution:
Let
n = number of gallons needed to obtain 24% ammonia
22
gallons (0.16) = n (.24)
<span>N = 14.67 gallons of water</span>