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3 years ago

9

Marvin collects trading cards.He stores them in boxes that hold 235 cards each.If Marvin has 4 boxes full of cards, how many car

ds does he have in his collection?
A)940
B)920
C)800
D)705

2 answers:

Taya2010 [7]3 years ago

5 0

235 * 4 = 940 your answer is A

makkiz [27]3 years ago

4 0

Well 4X235 gives you the answer is a 940

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Sherry took 18 hours to make jewelry for the county fair. It took her 2 1/4 times to sell it. How long did it take her to sell i

Ilia_Sergeevich [38]

18 x 2.25( because 1/4 =.25) = 40.5 hours.

4 0

3 years ago

Find the percent of discount (change) if an item that was priced at 54.00 is now on sale for 45.95

Semmy [17]

Answer:

about 14.9%

Step-by-step explanation:

Percent change can be computed using the formula ...

percent change = ((new value)/(old value) -1) × 100%

For the given numbers, this is ...

percent change = (45.95/54.00 -1) × 100% ≈ -14.907%

The discount is about 14.9%.

_____

Computed this way, the sign of the percentage change is negative for a decrease (discount), and positive for an increase.

3 0

4 years ago

The vector (a) is a multiple of the vector (2i +3j) and (b) is a multiple of (2i+5j) The sum (a+b) is a multiple of the vector (

kow [346]

Answer:

$\|a\| = 5\sqrt{13}$ .

$\|b\| = 3\sqrt{29}$ .

Step-by-step explanation:

Let $m$ , $n$ , and $k$ be scalars such that:

$\displaystyle a = m\, (2\, \vec{i} + 3\, \vec{j}) = m\, \begin{bmatrix}2 \\ 3\end{bmatrix}$ .

$\displaystyle b = n\, (2\, \vec{i} + 5\, \vec{j}) = n\, \begin{bmatrix}2 \\ 5\end{bmatrix}$ .

$\displaystyle (a + b) = k\, (8\, \vec{i} + 15\, \vec{j}) = k\, \begin{bmatrix}8 \\ 15\end{bmatrix}$ .

The question states that $\| a + b \| = 34$ . In other words:

$k\, \sqrt{8^{2} + 15^{2}} = 34$ .

$k^{2} \, (8^{2} + 15^{2}) = 34^{2}$ .

$289\, k^{2} = 34^{2}$ .

Make use of the fact that $289 = 17^{2}$ whereas $34 = 2 \times 17$ .

$\begin{aligned}17^{2}\, k^{2} &= 34^{2}\\ &= (2 \times 17)^{2} \\ &= 2^{2} \times 17^{2} \end{aligned}$ .

$k^{2} = 2^{2}$ .

The question also states that the scalar multiple here is positive. Hence, $k = 2$ .

Therefore:

$\begin{aligned} (a + b) &= k\, (8\, \vec{i} + 15\, \vec{j}) \\ &= 2\, (8\, \vec{i} + 15\, \vec{j}) \\ &= 16\, \vec{i} + 30\, \vec{j}\\ &= \begin{bmatrix}16 \\ 30 \end{bmatrix}\end{aligned}$ .

$(a + b)$ could also be expressed in terms of $m$ and $n$ :

$\begin{aligned} a + b &= m\, (2\, \vec{i} + 3\, \vec{j}) + n\, (2\, \vec{i} + 5\, \vec{j}) \\ &= (2\, m + 2\, n) \, \vec{i} + (3\, m + 5\, n) \, \vec{j} \end{aligned}$ .

$\begin{aligned} a + b &= m\, \begin{bmatrix}2\\ 3 \end{bmatrix} + n\, \begin{bmatrix} 2\\ 5 \end{bmatrix} \\ &= \begin{bmatrix}2\, m + 2\, n \\ 3\, m + 5\, n\end{bmatrix}\end{aligned}$ .

Equate the two expressions and solve for $m$ and $n$ :

$\begin{cases}2\, m + 2\, n = 16 \\ 3\, m + 5\, n = 30\end{cases}$ .

$\begin{cases}m = 5 \\ n = 3\end{cases}$ .

Hence:

$\begin{aligned} \| a \| &= \| m\, (2\, \vec{i} + 3\, \vec{j})\| \\ &= m\, \| (2\, \vec{i} + 3\, \vec{j}) \| \\ &= 5\, \sqrt{2^{2} + 3^{2}} = 5 \sqrt{13}\end{aligned}$ .

$\begin{aligned} \| b \| &= \| n\, (2\, \vec{i} + 5\, \vec{j})\| \\ &= n\, \| (2\, \vec{i} + 5\, \vec{j}) \| \\ &= 3\, \sqrt{2^{2} + 5^{2}} = 3 \sqrt{29}\end{aligned}$ .

6 0

3 years ago

ShoeShop is having a sale on flip-flops. The first 2 pairs cost $8.50 each plus each additional pair costs $3.75. Mrs. Tyler can

olga55 [171]

No matter what, if you get at least 2 pair of flip flops you will be spending $8.50. So that's the amount you're going to spend plus 3.75 per pair after that. If she has $34.75 to spend and cannot go over, the inequality sign will be less than or equal to. It's ok if she spends less than that and it's ok if she spends exactly that, but she cannot spend more than she has. The inequality then would be this: $3.75p+8.50 \leq 34.75$

7 0

3 years ago

Read 2 more answers

What is the angle of DBC

Licemer1 [7]

When added, these two angles are supplementary, meaning that their sum is 180. This means that we can do the following to find x, and eventually DBC:

3x+67+4x+50=180
Simplifies to:
7x+117=180
Then by the Subtraction Prop. of Equality:
7x=63
Then divide by 7 on both sides to get that x=9.

We then substitute 9 into angle DBC.
4(9)+50
=36+50
DBC=86

:)

8 0

4 years ago