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.
Answer:
KL = 10
Step-by-step explanation:
JK + KL = JL
2x – 2 + x – 9 = 2x + 8
Combine like terms
3x -11 = 2x+8
Subtract 2x from each side
3x-2x -11 = 2x+8-2x
x-11 = 8
Add 11 to each side
x-11+11 = 8+11
x = 19
KL = x – 9
= 19-9
= 10
the sequence is in multiples of 4 (2*4=8, 8*4=32, 32*4=128)
so 128*4=512, 512*4=2048, 2048*4=8192 & 8192*4=32768
2+8+32+128+512+2048+8192+32768=43690
Answer:
The correct answer is b.
Step-by-step explanation:
The wave equation is given generally as:
c(x, t) = Acos(kx - wt)
Where A = amplitude
k = wave number
w = angular frequency.
x = horizontal distance moves by the wave.
t = time
The options show to us that the wave depends only on t and not (x, t).
Hence, the wave equation becomes:
c(t) = Acos(wt)
Given that:
A = 5 V
f = 1 * 10⁶ Hz
Angular Frequency, w, is given as:
w = 2πf
w = 2 * π * 1 * 10⁶ Hz
w = 2π(1 * 10⁶)
The wave equation becomes:
c(t) = 5cos(2*π*1*10⁶)
The correct answer is b.