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2 years ago

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Lucy spent 3/5 of her money on a handbag. She spent the remainder on 3 T-shirts which cost $4 each. How much did the handbag cos

t?

1 answer:

mixer [17]2 years ago

5 0

Answer:

I’m pretty sure there’s not enough informatio, what did she start with? A better problem would be ”Lucy started with $15 dollars. She spent 3/5 of her money on a hand bag, she then spent the remainer on 3 shirts that cost $4 each. How much did her handbag cos?” then we would add 3+4 which equals 7 then count how much till we get to $15 (the money which she starts with) then we would know that that hand bag cost $8 (7+8=15)

Step-by-step explanation:

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Solve 11 - 1/2y= 3 + 6x for y.

Ilia_Sergeevich [38]

Answer:

y = 12x+16

Step-by-step explanation:

Simplify both sides of the equation then isolate the variable.

Step 1, add 11 to both sides.

−1 /2 y+11+−11=6x+3+−11

−1 /2 y=6x−8

Step 2, divide both sides by (-1)/2.

You will be left with

y = 12x+16

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2 years ago

Jake, Daniel, Timmy, Amy, and Pam are going on a fishing trip. They are taking a pick-up truck which only holds 3 people inside

VashaNatasha [74]

Answer:

It has to be Timmy and it is 412.

Step-by-step explanation:

Uh I did it in my head and it is really hard to explain.

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2 years ago

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The center of a circle is at the origin on a coordinate grid. The vertex of a parabola that opens upward is at (0, 9). If the ci

zhannawk [14.2K]

Answer:

"The maximum number of solutions is one."

Step-by-step explanation:

Hopefully the drawing helps visualize the problem.

The circle has a radius of 9 because the vertex is 9 units above the center of the circle.

The circle the parabola intersect only once and cannot intercept more than once.

The solution is "The maximum number of solutions is one."

Let's see if we can find an algebraic way:

The equation for the circle given as we know from the problem without further analysis is so far $x^2+y^2=r^2$ .

The equation for the parabola without further analysis is $y=ax^2+9$ .

We are going to plug $ax^2+9$ into $x^2+y^2=r^2$ for $y$ .

$x^2+y^2=r^2$

$x^2+(ax^2+9)^2=r^2$

To expand $(ax^2+9)^2$ , I'm going to use the following formula:

$(u+v)^2=u^2+2uv+v^2$ .

$(ax^2+9)^2=a^2x^4+18ax^2+81$ .

$x^2+y^2=r^2$

$x^2+(ax^2+9)^2=r^2$

$x^2+a^2x^4+18ax^2+81=r^2$

So this is a quadratic in terms of $x^2$

Let's put everything to one side.

Subtract $r^2$ on both sides.

$x^2+a^2x^4+18ax^2+81-r^2=0$

Reorder in standard form in terms of x:

$a^2x^4+(18a+1)x^2+(81-r^2)=0$

The discriminant of the left hand side will tell us how many solutions we will have to the equation in terms of $x^2$ .

The discriminant is $B^2-4AC$ .

If you compare our equation to $Au^2+Bu+C$ , you should determine $A=a^2$

$B=(18a+1)$

$C=(81-r^2)$

The discriminant is

$B^2-4AC$

$(18a+1)^2-4(a^2)(81-r^2)$

Multiply the (18a+1)^2 out using the formula I mentioned earlier which was:

$(u+v)^2=u^2+2uv+v^2$

$(324a^2+36a+1)-4a^2(81-r^2)$

Distribute the 4a^2 to the terms in the ( ) next to it:

$324a^2+36a+1-324a^2+4a^2r^2$

$36a+1+4a^2r^2$

We know that $a>0$ because the parabola is open up.

We know that $r>0$ because in order it to be a circle a radius has to exist.

So our discriminat is positive which means we have two solutions for $x^2$ .

But how many do we have for just $x$ .

We have to go further to see.

So the quadratic formula is:

$\frac{-B \pm \sqrt{B^2-4AC}}{2A}$

We already have $B^2-4AC}$

$\frac{-(18a+1) \pm \sqrt{36a+1+4a^2r^2}}{2a^2}$

This is t he solution for $x^2$ .

To find $x$ we must square root both sides.

$x=\pm \sqrt{\frac{-(18a+1) \pm \sqrt{36a+1+4a^2r^2}}{2a^2}}$

So there is only that one real solution (it actually includes 2 because of the plus or minus outside) here for x since the other one is square root of a negative number.

That is,

$x=\pm \sqrt{\frac{-(18a+1) \pm \sqrt{36a+1+4a^2r^2}}{2a^2}}$

means you have:

$x=\pm \sqrt{\frac{-(18a+1)+\sqrt{36a+1+4a^2r^2}}{2a^2}}$

or

$x=\pm \sqrt{\frac{-(18a+1)-\sqrt{36a+1+4a^2r^2}}{2a^2}}$ .

The second one is definitely includes a negative result in the square root.

18a+1 is positive since a is positive so -(18a+1) is negative

2a^2 is positive (a is not 0).

So you have (negative number-positive number)/positive which is a negative since the top is negative and you are dividing by a positive.

We have confirmed are max of one solution algebraically. (It is definitely not 3 solutions.)

If r=9, then there is one solution.

If r>9, then there is two solutions as this shows:

$x=\pm \sqrt{\frac{-(18a+1)+\sqrt{36a+1+4a^2r^2}}{2a^2}}$

r=9 since our circle intersects the parabola at (0,9).

Also if (0,9) is intersection, then

$0^2+9^2=r^2$ which implies r=9.

Plugging in 9 for r we get:

$x=\pm \sqrt{\frac{-(18a+1)+\sqrt{36a+1+4a^2(9)^2}}{2a^2}}$

$x=\pm \sqrt{\frac{-(18a+1)+\sqrt{36a+1+324a^2}}{2a^2}}$

$x=\pm \sqrt{\frac{-(18a+1)+\sqrt{(18a+1)^2}}{2a^2}}$

$x=\pm \sqrt{\frac{-(18a+1)+18a+1}{2a^2}}$

$x=\pm \sqrt{\frac{0}{2a^2}}$

$x=\pm 0$

$x=0$

The equations intersect at x=0. Plugging into $y=ax^2+9$ we do get $y=a(0)^2+9=9$ .

After this confirmation it would be interesting to see what happens with assume algebraically the solution should be (0,9).

This means we should have got x=0.

$0=\frac{-(18a+1)+\sqrt{36a+1+4a^2r^2}}{2a^2}$

A fraction is only 0 when it's top is 0.

$0=-(18a+1)+\sqrt{36a+1+4a^2r^2}$

Add 18a+1 on both sides:

$18a+1=\sqrt{36a+1+4a^2r^2$

Square both sides:

$324a^2+36a+1=36a+1+4a^2r^2$

Subtract 36a and 1 on both sides:

$324a^2=4a^2r^2$

Divide both sides by $4a^2$ :

$81=r^2$

Square root both sides:

$9=r$

The radius is 9 as we stated earlier.

Let's go through the radius choices.

If the radius of the circle with center (0,0) is less than 9 then the circle wouldn't intersect the parabola. So It definitely couldn't be the last two choices.

7 0

2 years ago

Read 2 more answers

A school pays $1,825 for 150 shirts. This includes the $25 flat-rate shipping cost.

yKpoI14uk [10]

Answer:

a)

We know that the total cost for the 150 shirts (plus a flat-rate of $25) is $1,825.

First, let's find how much costs each shirt.

First, the total cost of the shirts alone (neglecting the flat-rate) is:

$1,825 - $25 = $1,800

Then each shirt costs equal to the quotient of the cost and the number of shirts:

$1,800/150 = $12

Each shirt costs $12.

Then if you order T shirts, the total cost will be the flat-rate of $25 plus T times $12. The equation is:

C(T) = $25 + T*$12

b) C represents the cost

T represents the number of shirts ordered.

c) The initial value is the constant value, in this case, is $25

The rate of change is the coefficient that multiplies the independent variable (T), in the equation the rate of change is $12.

7 0

2 years ago

The fish population of Lake Collins is decreasing at a rate of 3% per year. In 2004 there were about 1,300 fish. Write an expone

Sergeu [11.5K]

For this case we have a function of the form:
$y = A * (b) ^ x
$ Where,
A: initial amount
b: decrease rate
x: time in years
Substituting values we have:
$y = 1300 * (0.97) ^ x
$
For 2010 we have:
$y = 1300 * (0.97) ^ 6

y = 1083$
Answer:
an exponential decay function to model this situation is:
y = 1300 * (0.97) ^ x
The population in 2010 is:
y = 1083

6 0

2 years ago

Read 2 more answers