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 answer is 24 because 8 times 3 is 24
I swear if it’s wrong I’m sorry ok but it’s 3 for me
Answer:
793.25 mi/hr
Step-by-step explanation:
Given that:
The radius of the earth is = 3030 miles
The angular velocity = 
If a jet flies due west with the same angular velocity relative to the ground at the equinox;
We are to determine the How fast in miles per hour would the jet have to travel west at the 40th parallel for this to happen.
NOW;
Distance s is expressed by the relation
s = rθ

s = 793.25
The speed which depicts how fast in miles per hour the jet would have traveled is :


v = 793.25 mi/hr
Hence, the jet would have traveled 793.25 mi/hr due west at the 40th parallel for this to happen.