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MAXImum [283]
3 years ago
9

A mixture of 30 pounds of candy sells for $1.10 a pound. The mixture consists of chocolates worth $1.50 a pound and chocolates w

orth 90¢ a pound. How many pounds of the $1.50 chocolate were used to make the mixture?
A)15
B)10
C)12
Mathematics
1 answer:
astra-53 [7]3 years ago
3 0
x-chocolate\ worth\ 1,50\$ \ per\ pound\\
y-chocolate\ worth\ 0,9\$\ per\ pound\\
\\\\
 \left \{ {{x+y=30} \atop {30*1,10=x*1,50+y*0,9}} \right.\\\\ \left \{ {{x=30-y} \atop {33=1,5x+0,9y}} \right. \\\\ Using \ substitution\ method:\\\\33=1,5(30-y)+0,9y\\\\
33=45-1,5y+0,9y\\\\ -12=-0,6y\ |:-0,6\\\\
y=20\\
x=10
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For each equation, determine whether it represents a direct variation, an inverse variation, or neither.
Murljashka [212]

Direct variation is written in the form y = k * x or x = y * k. And, inverse variation is written in the form y = k/x or x = y/k.

For the first problem, if we isolated the y, we would get:

4y = 3x - 1

y = (3/4)x - 1/4

This is written as y = mx + b, which isn’t the form of direct or inverse variation, so the answer is NEITHER.

For the second equation, we could divide by 2 on both sides to isolate x and see if it is in the correct form:

x = 4/y

This is inverse form, so the second question is INVERSE with a constant of variation as 4.

8 0
3 years ago
HEY can some please help me out I will give you BRAINLEST!!!
kondaur [170]

Answer:

b the second 1

Step-by-step explanation:

4 0
3 years ago
Make q the subject of the formula
miss Akunina [59]

Answer:

q = 2p - 1/3

Step-by-step explanation:

2q + 2p = 1+5q

2q = 1+5q-2p

-3q=1-2p

-q = 1-2p/3

q= 2p-1/3

8 0
2 years ago
Read 2 more answers
I really don't get these questions
Mazyrski [523]

Answer:

B

Step-by-step explanation:

280 + 5(–5) + (–42) + 2(75) + (–200)

280 - 25 - 42 + 150 - 200

280 - 67 + 150 - 200

280 - 67 - 50

213 - 50

= $163

3 0
3 years ago
Find the quadratic function y=​f(x) whose graph has a vertex ​(−3​,4​) and passes through the point ​(−7​,0). Write the function
olganol [36]

Answer:

Step-by-step explanation:

This is a parabola since a quadratic is a parabola.  The standard form for a parabola is y = ax² + bx + c

but before we do that, we will use the vertex form, since it will make our work easier at the beginning.  

First and foremost, when we plot the vertex and the given point, the vertex is higher up than is the point; that means that this parabola opens upside down, and its vertex form will be

y=-|a|(x - h)² + k

The absolute value is out in front of the a, so we know that the value of a is positive, but the quadratic itself is negative (upside down) and we will find that math takes care of that negative that needs to be out front.  So we need to solve for a by filling in the x, y, h, and k values from the point and the vertex:  x = -7, y = 0, h = -3, k = 4

0 = a(-7 - (-3))² + 4 and

0 = a(-7 + 3)² + 4 and

0 = a(-4)² + 4 and

0 = a(16) + 4 and

0 = 16a + 4 and

-4 = 16a so

a=-\frac{1}{4}

Now that we know a, we can plug it back into the vertex form and then put it into standard form from there.

y=-\frac{1}{4}(x+3)^2+4

Now we will FOIL out what's inside the parenthesis to get

y=-\frac{1}{4}(x^2+6x+9)+4

Simplify by distributing the -1/4 into the parenthesis:

y=-\frac{1}{4}x^2-\frac{3}{2}x-\frac{9}{4}+4

Combine like terms to get

y=-\frac{1}{4}x^2-\frac{3}{2}x+\frac{7}{4}

And there you go!

5 0
3 years ago
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