Answer:
22
Step-by-step explanation:
You add up the value of each X and you get a final answer of 22. Have a great day!
Answer: 490 grams of the first alloy should be used.
30 grams of the second alloy should be used.
Step-by-step explanation:
Let x represent the weight of the first alloy in grams that should be used.
Let y represent the weight of the second alloy in grams that should be used.
A chemist has two alloys, one of which is 15% gold and 20% lead. This means that the amount of gold and lead in the first alloy is
0.15x and 0.2x
The second alloy contains 30% gold and 50% lead. This means that the amount of gold and lead in the second alloy is
0.3y and 0.5y
If the alloy to be made contains 82.5 g of gold, it means that
0.15x + 0.3y = 82.5 - - - - - - - - - - - -1
The second alloy would also contain 113 g of lead. This means that
0.2x + 0.5y = 113 - - - - - - - - - - - - -2
Multiplying equation 1 by 0.2 and equation 2 by 0.15, it becomes
0.03x + 0.06y = 16.5
0.03x + 0.075y = 16.95
Subtracting, it becomes
- 0.015y = - 0.45
y = - 0.45/- 0.015
y = 30
Substituting y = 30 into equation 1, it becomes
0.15x + 0.3 × 30 = 82.5
0.15x + 9 = 82.5
0.15x = 82.5 - 9 = 73.5
x = 73.5/0.15
x = 490
Answer:
Sample proportion ; phat
x / n
Step-by-step explanation:
The sample proportion may be explained as a proportional representation of part of the population or larger sample which have a certain character or exhibit a particular trait.
The sample proportion is expressed Mathematically as ;
phat = x / n
x = number of subjects with a specified characteristic ;
n = total sample size
For instance ;
The proportion of black balls in a sample of 100 balls is 15 ; the sample proportion of bla k balls will be :
phat = x / n = 15 / 100 = 0.15
Part A
The exponential model that describes the situation
The formula is
Y (x)=400 (1+0.02/4)^4x
Y (x)=400 (1+0.005)^4x
Y (x)=400 (1.005)^4x
Where x is the number of years
Part B
The value of the account after 5 years
Y (5)=400×(1.005)^(4×5)
Y (5)=441.96
Y = 3x + 3 this is equation 1
y = x -1 this is equation 2
since equation 1 and 2 already defined y in terms of x, we're just gonna substitute y into the other equation. as 2 is shorter I'm going with that today
x - 1 = 3x +3
-1 - 3 = 3x - x
-4 = 2x
x = -2
now we've got x just sub it in equation 2
y = -2 -1
y = -3
so the answer is (-2,-3)
