18 kg of 15% copper and 72 kg of 60% copper should be combined by the metalworker to create 90 kg of 51% copper alloy.
<u>Step-by-step explanation:</u>
Let x = kg of 15% copper alloy
Let y = kg of 60% copper alloy
Since we need to create 90 kg of alloy we know:
x + y = 90
51% of 90 kg = 45.9 kg of copper
So we're interested in creating 45.9 kg of copper
We need some amount of 15% copper and some amount of 60% copper to create 45.9 kg of copper:
0.15x + 0.60y = 45.9
but
x + y = 90
x= 90 - y
substituting that value in for x
0.15(90 - y) + 0.60y = 45.9
13.5 - 0.15y + 0.60y = 45.9
0.45y = 32.4
y = 72
Substituting this y value to solve for x gives:
x + y = 90
x= 90-72
x=18
Therefore, in order to create 90kg of 51% alloy, we'd need 18 kg of 15% copper and 72 kg of 60% copper.
The first option,
both have to be negative, because they were originally both part of the one fraction, which was all negative.
Answer:
725.7
Step-by-step explanation:
you multiply 682.98 x 6.25% and get 42.68625
then you add 682.98 + 42.68625 and get 725.66625
then you have to round to the nearest hundredth and get 725.7.
You first find the average of the first two test scores. When you find the average, you add the two numbers together and then divide by two which gives you 89. You then plug in different scores above the number 89 and find the average of those (89 and x) to see which gives you an average of 92. It’s mostly a guess and check type of problem.
The distance between the point (3, 5) and a line with the equation 5x – 3y + 10 = 0 will be 10 / √(34) units.
<h3>What is the distance between a point and a line?</h3>
Let (x₁, y₁) be the point and ax + by + c = 0 be the line.
Then the distance between a point and a line will be
The point (3, 5) and a line with the equation 5x – 3y + 10 = 0.
Then the distance between them will be
Learn more about the distance between a point and a line here;
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