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
The experimental units in this experiment are the 10 plants in group 2.
The experimental unit is a term used in science to refer to an individual or group of objects that are initially equivalent and then undergo experimental processes.
According to the above, the experimental unit of this experiment is the group 2 of plants because these are the plants that are going to be put into experimentation with a new fertilizer.
Then, the answer is D, because it refers to the experimental unit corresponding to this experiment.
Learn more in: brainly.com/question/17034824
Answer:
(x+3)^2 +(y-5)^2 = 36
Step-by-step explanation:
We can write the equation of a circle as
(x-h)^2 +(y-k)^2 = r^2 where (h,k) is the center and r is the radius
(x- -3)^2 +(y-5)^2 = 6^2
(x+3)^2 +(y-5)^2 = 36
Answer:
7/2
Step-by-step explanation:
