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 D
Explanation:22.5 is how much each vaccine is and x is how many vaccines while y is the total cost and 45 is a standard fee
<span>|5x - 1| < 1
-1 < 5x - 1 < 1
-1 + 1 < 5x < 1 + 1
0 < 5x < 2
0/5 < x < 2/5
0 < x < 2/5
</span>
Answer:
205
Step-by-step explanation:
Given
N(t) = 100 + 15t is the equation of the relation.
We're asked to find N(7)
Taking a look at the question again and putting it side by side the equation
N(t)
N(7)
We can deduce that t = 7, and as such, solve for it in the equation given
N(7) = 100 + 15(7)
N(7) = 100 + 105
N(7) = 205
Therefore, the number of unread mails after 7 days will be 205
Answer:
Step-by-step explanation:
Start off by explaining that u know this(don't use these exact word though :A composite number is a positive integer that can be formed by multiplying two smaller positive integers Equivalently. A prime number is a natural number greater than 1 that is not a product of two smaller natural numbers.... I couldn't really see the whole page so this is what i could get for u.... Good luck
