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.
Infinitely many because if you subtract 7x from both sides, you get 4 = 4, which is true at all times no matter what x is.
Answer:
D (x-10)
Step-by-step explanation:
x^2 - 8x - 20
(x -10)(x+2)
You have not provided the figures, therefore, I cannot provide an exact answer.
However, I can helps you with the steps.
One important thing to note is that when writing statements of congruency, the order of writing the letters is very important. This is because each side/angle in the first figure would be congruent to the corresponding side/angle in the second.
Therefore, all you have to do in the above question is write the congruent figures and determine the corresponding congruent sides/angles
Example:
If we are given that triangle ABC is congruent to triangle DEF
This means that:
AB = DE
BC = EF
AC = DF
angle A = angle D
angle B = angle E
angle C = angle F
Hope this helps :)
3x+50 = 6x - 10
6x -3x = 50+10
3x = 60
x = 20
answer
x = 20
