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:
Step-by-step explanation:
Hi there!
To get rid of the fraction 
, multiply both sides of the equation by 3 (the denominator):
To get rid of the fraction 
, multiply both sides of the equation by 5 (the denominator):
I hope this helps!
The answer is 61.5
Please mark as brainliest; have a blessed day!
She plays soccer and golf for a total of 125 minutes:
s + g = 125
She plays soccer 45 minutes more than she plays golf:
s = g + 45 this is for A
B= 40 minutes of golf everyday
C= Yes, because in fact, she plays 85 minutes of soccer everyday, and 85 is greater than 80, so yes she CAN play 80 minutes of soccer every day. Perhaps they meant possible to spend ONLY 80 minutes, then NO, that wouldn't be possible, because then by playing 45 minutes more soccer than golf, she wouldn't have played enough to have 125 total minutes of total play. Technically the way the question is worded, the answer is yes.
I hope this helps!
