Answer:
Step-by-step explanation:
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:-7x+2y=2
Step-by-step explanation:
(-2x+y=8)-(5x-y=6)
(-2x+y=8)> this side change since it’s negative
(-2x+y=8) - (-5x+y=-6)
-7x+2y=2
Answer:
1260 inches
Step-by-step explanation:
Calculator
Answer: a) 2092278989 b) 576, c) 
Step-by-step explanation:
Since we have given that
Number of students = 16
Number of desks = 16
a) How many days must pass before the class must repeat a seating arrangement?
If the number of rows = 4
b) How many seating arrangements are there that put Larry, Moe, Curly, and Shemp in the front seats?
c) How many seating arrangements are there that put Larry, Moe, Curly, and Shemp in the front seats?
Hence, a) 2092278989 b) 576, c)
