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4 years ago

11

The Sheng family had dinner at their favorite restaurant. A 4% sales tax was added to their bill. Amy paid the bill with a $25 g

ift certificate plus $44.80. How much did the family's dinner cost before tax? Round your answer to the nearest penny.$ 71.59$ 66.01$ 67.12$ 67.01

2 answers:

emmainna [20.7K]4 years ago

7 0

The total cost is 72.59 so it should be A I believe

kirill115 [55]4 years ago

5 0

The answer would be 67.12.

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ollegr [7]

1)
2x^2 - 13x - 24 = 0;
the discriminant is : ( - 13 )^2 - 4 * 2 * ( -24 ) = 169 + 192 = 361 = 19^2 => we have two different rational-number solutions ;

2)
[ -2( x + 2 ) - 3( x - 5 ) ] / [ ( x - 5 )( x + 2 ) ] < 0 <=>

( -5x + 11 ) /  [ ( x - 5 )( x + 2 ) ] < 0

We have 2 situations :
a) - 5x + 11 < 0 and  ( x - 5 )( x + 2 ) > 0 => x∈ ( 11 / 5 , + oo ) and x∈( -oo, - 2 )U
( 5 , + oo ) => x∈( 5, +oo);
b)   - 5x + 11 > 0 and  ( x - 5 )( x + 2 ) < 0 => x∈(-oo, 11/5) and x∈( -2, 5 ) =>
x∈( -2, 11/5 );

Finally, x∈ U (-2, 11 / 5 ) U ( 5, +oo).

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3 years ago

40(x-2)=2/5(x+4)<br><br><br> Please help

kherson [118]

Answer:

x = 68/33

Explanation:

Step 1: Simplify both sides of the equation.

Step 2: Subtract 2/5x from both sides.

Step 3: Add 80 to both sides.

Step 4: Multiply both sides by 5/198.

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4 years ago

A data mining routine has been applied to a transaction dataset and has classified 88 records as fraudulent (30 correctly so) an

chubhunter [2.5K]

Answer:

The classification matrix is attached below

Part a

The classification error rate for the records those are truly fraudulent is 65.91%.

Part b

The classification error rate for records that are truly non-fraudulent is 96.64%

Step-by-step explanation:

The classification matrix is obtained as shown below:

The transaction dataset has 30 fraudulent correctly classified records out of 88 records, that is, 30 records are correctly predicted given that an instance is negative.

Also, there would be 88 - 30 = 58 non-fraudulent incorrectly classified records, that is, 58 records are incorrectly predicted given that an instance is positive.

The transaction dataset has 920 non-fraudulent correctly classified records out of 952 records, that is, 920 records are correctly predicted given that an instance is positive.

Also, there would be 952 - 920 = 32 fraudulent incorrectly classified records, that is, 32 records incorrectly predicted given that an instance is negative.

That is,

Predicted value

Active value Fraudulent Non-fraudulent

Fraudlent 30 58

non-fraudulent 32 920

The classification matrix is obtained by using the information related to the transaction data, which is classified into fraudulent records and non-fraudulent records.

The error rate is obtained as shown below:

The error rate is obtained by taking the ratio of $\left( {b + c} \right)(b+c)$ and the total number of records.

The classification matrix is, shown above

The total number of records is, $30 + 58 + 32 + 920 = 1,040$

The error rate is,

$\begin{array}{c}\\{\rm{Error}}\,{\rm{rate}} = \frac{{b + c}}{{{\rm{Total}}}}\\\\ = \frac{{58 + 32}}{{1,040}}\\\\ = \frac{{90}}{{1,040}}\\\\ = 0.0865\\\end{array}$

The percentage is $0.0865 \times 100 = 8.65$

(a)

The classification error rate for the records those are truly fraudulent is obtained by taking the rate ratio of b and $\left( {a + b} \right)(a+b)$ .

The classification error rate for the records those are truly fraudulent is obtained as shown below:

The classification matrix is, shown above and in the attachment

The error rate for truly fraudulent is,

$\begin{array}{c}\\FP = \frac{b}{{a + b}}\\\\ = \frac{{58}}{{30 + 58}}\\\\ = \frac{{58}}{{88}}\\\\ = 0.6591\\\end{array}$

The percentage is, $0.6591 \times 100 = 65.91$

(b)

The classification error rate for records that are truly non-fraudulent is obtained by taking the ratio of d and $\left( {c + d} \right)(c+d)$ .

The classification error rate for records that are truly non-fraudulent is obtained as shown below:

The classification matrix is, shown in the attachment

The error rate for truly non-fraudulent is,

$\begin{array}{c}\\TP = \frac{d}{{c + d}}\\\\ = \frac{{920}}{{32 + 920}}\\\\ = \frac{{920}}{{952}}\\\\ = 0.9664\\\end{array}$

The percentage is, $0.9664 \times 100 = 96.64$

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3 years ago

N a soccer game, Sally kicks the ball to a teammate who is on the other side of the field. The ball's height h (in feet above th

tresset_1 [31]

Answer:

At the time that it is kicked, the ball is on the ground, that is, it's height is 0 feet.

Step-by-step explanation:

The height of the ball after t seconds is given by the following equation:

$h(t) = -2t^{2} + 10t$

What is the height of the ball at the time it is kicked?

The ball is kicked at t = 0.

So we have to find h(0)

$h(0) = -2*0^{2} + 10*0 = 0$

At the time that it is kicked, the ball is on the ground, that is, it's height is 0 feet.

8 0

4 years ago

The answer to the first question

Olenka [21]

The answer of number 4 is 57+36 x 0.001

6 0

3 years ago