This was my answer for someone else question exactly like this :)
Answer:
Equivalent. 0.4(k+3)=0.4k+1.2
Step-by-step explanation:
x means multiplication. k is the variable.
Hi.
So, you have to distribute the 0.4 into the parenthesis to get rid of them. So, you do 0.4xk, which is just 0.4k, and 0.4x3, which is 1.2. So, you have 0.4k+1.2, which means it is Equivalent.
Answer A) x-11
Hope this helps!
Answer:
Tim
Step-by-step explanation:
Tim drove 62 miles per hour you get this by dividing 217 by 3.5 and then you divide Emily's. 244/4 and you get 61
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.
