Write a formula to find any number in row B.

A metallurgist needs to make 12.4 lb. of an 10) alloy containing 50% gold. He is going to melt and combine one metal that is 60%

sergeinik [125]

Now, let's say, we add "x" lbs of the 60% gold alloy, so.. how much gold is in it? well, is just 60%, so (60/100) * x, or 0.6x.

likewise, if we use "y" lbs of the 40% alloy, how much gold is in it? well, 40% of y, or (40/100) * y, or 0.4y.

now, whatever "x" and "y" are, their sum must be 12.4 lbs.

we also know that the gold amount in each added up, must equal that of the 50% resulting alloy.

$\bf \begin{array}{lccclll}
&\stackrel{lbs}{amount}&\stackrel{gold~\%}{quantity}&\stackrel{gold}{quantity}\\
&------&------&------\\
\textit{60\% alloy}&x&0.6&0.6x\\
\textit{40\% alloy}&y&0.4&0.4y\\
------&------&------&------\\
\textit{50\% alloy}&12.4&0.50&6.2
\end{array}$

$\bf \begin{cases}
x+y=12.4\implies \boxed{y}=12.4-x\\
0.6x+0.4y=6.2\\
-------------\\
0.6x+0.4\left( \boxed{12.4-x} \right)=6.2
\end{cases}
\\\\\\
0.6x-0.4x+4.96=6.2\implies 0.2x=1.24\implies x=\cfrac{1.24}{0.2}
\\\\\\
x=\stackrel{lbs}{6.2}$

how much of the 40% alloy? well, y = 12.4 - x.

5 0

4 years ago

The domain of f(x) = -2x + 5 is {-2, -1, 0, 1, 2}. What is the range.?

Naily [24]

Answer:

{9, 7, 5, 3, 1}

Step-by-step explanation:

All you do is plus in each domain value in for the x and you get the range every time.

-2(-2)+5

-2(-1)+5

-2(0)+5

-2(1)+5

-2(2)+5

3 0

3 years ago

What the value of p in the question shown

hammer [34]

It would be D because you have to do the cube root on both sides. What I do is ignore the decimal and add it in later once the math is complete like on this question you can tell by process of elimination that 8 squared is 64 but you’re look for the cube root so that eliminates a and c and now just make sure the decimal is in the right place

5 0

3 years ago

Does the graph of the equation y = 7 - 2x increase or decrease? A) decreases because the x values decrease from left to right B)

Nutka1998 [239]

Y=mx+b
m=slope=rise/run
if slope>0, then it increases
if slope<0, then decreases because it is going down

y=7-2x
y=-2x+7
-2<0
decreasing
because the y values decrease from left to right
the x values always increase if you go from left to right

B is the answer

7 0

3 years ago

Read 2 more answers

• Puzzle refer to the above attachment .

dem82 [27]

The solution to this puzzle is 10+3 = 13

<h3>How to solve the puzzle</h3>

To solve this the values at the top of the star were gotten by the addition of two values inside the stars.

3 + 12 = 15
12 + 4 = 16
4 + 2 = 6
2 + 10 = 12
10 + 3 = 13

Therefore the answer to this question is 13.

Another way of getting the value is by adding 15 + 16 = 31

12 + 6 = 18

31-18 = 13