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Paladinen [302]
1 year ago
14

On two investments totaling $6,000, Brian lost 7% on one and earned 8% on the other. If his net annual receipts were $420, how m

uch was each investment?
Mathematics
1 answer:
lianna [129]1 year ago
8 0

Answer:

the amount of money invested at the rate of 7% is $400

the amount of money invested at the rate of 8%. Is $5600

Step-by-step explanation:

Let x represent the amount of money invested at the rate of 7%.

Let y represent the amount of money invested at the rate of 8%.

The total amount of money that Brian invested is $6000. This means that

x + y = 6000

The formula for simple interest is expressed as

I = PRT/100

Where

P represents the principal

R represents interest rate

T represents time

Considering the investment at the rate at 7%,

P = x

R = 7%

T = 1

I = (x × 7 × 1)/100 = 0.07x

Considering the investment at the rate of 8%,

P = y

R = 8

T = 1

I = (y × 8 × 1)/100 = 0.08y

If his net annual receipts were $420, it means that

0.08y - 0.07x = 420 - - - - - - - - -1

Substituting x = 6000 - y into equation 1, it becomes

0.08y - 0.07(6000 - y) = 420

0.08y - 420 + 0.07y = 420

0.08y + 0.07y = 420 + 420

0.15y = 840

y = 840/0.15 = 5600

x = 6000 - y = 6000 - 5600

x = 400

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Answer:

1.99385kg of chicken was eaten.

Step-by-step explanation:

We first need to know how many grams were left in kilograms, so we can find the difference.

Unit conversion: 6.15g x 1kg/1000g = 0.00615kg

Eaten amount of chicken: 2kg - 0.00615kg = 1.99385kg

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3 0
1 year ago
Find the eccentricity, b. identify the conic, c. give an equation of the directrix, and d. sketch the conic.
densk [106]

Answer:

a) 10/3  

b) hyperbola

c) x = ± 6/5

Step-by-step explanation:

a) A conic section with a focus at the origin, a directrix of x = ±p where p is a positive real number and positive eccentricity (e) has a polar equation:

r=\frac{ep}{1\pm e*cos\theta}

Given the conic equation: r=\frac{12}{3-10cos\theta}

We have to make it to be in the form r=\frac{ep}{1\pm e*cos\theta}:

r=\frac{12}{3-10cos\theta}\\\\multiply\ both\ sides\ by\ \frac{1}{3} \\\\r=\frac{12*\frac{1}{3}}{(3-10cos\theta)*\frac{1}{3}}\\\\r=\frac{12*\frac{1}{3}}{3*\frac{1}{3}-10cos\theta*\frac{1}{3}}\\\\r=\frac{4}{1-\frac{10}{3}cos\theta } \\\\r=\frac{\frac{10}{3}(\frac{6}{5} ) }{1-\frac{10}{3}cos\theta }

Comparing with  r=\frac{ep}{1\pm e*cos\theta}

e = 10/3 = 3.3333, p = 6/5

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6 0
2 years ago
(b) A department store has 7,000 charge accounts. The comptroller takes a random sample of 36 of
galben [10]

Answer:

a.0.8664

b. 0.23753

c. 0.15866

Step-by-step explanation:

The comptroller takes a random sample of 36 of the account balances and calculates the standard deviation to be N42.00. If the actual mean (1) of the account balances is N175.00, what is the probability that the sample mean would be between

a. N164.50 and N185.50?

b. greater than N180.00?

c. less than N168.00?

We solve the above question using z score formula

z = (x-μ)/σ/√n where

x is the raw score,

μ is the population mean = N175

σ is the population standard deviation = N42

n is random number of sample = 36

a. Between N164.50 and N185.50?

For x = N 164.50

z = 164.50 - 175/42 /√36

z = -1.5

Probability value from Z-Table:

P(x = 164.50) = 0.066807

For x = N185.50

z = 185.50 - 175/42 /√36

z =1.5

Probability value from Z-Table:

P(x=185.50) = 0.93319

Hence:

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= 0.93319 - 0.066807

= 0.866383

Approximately = 0.8664

b. greater than N180.00?

x > N 180

Hence:

z = 180 - 175/42 /√36

z = 5/42/6

z = 5/7

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Probability value from Z-Table:

P(x<180) = 0.76247

P(x>180) = 1 - P(x<180) = 0.23753

c. less than N168.00?

x < N168.

z = 168 - 175/42 /√36

z = -7/42/6

z = -7/7

z = -1

Probability value from Z-Table:

P(x<168) = 0.15866

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1 year ago
The students at Barton academy are planning a fundraiser to give money to an organization in their community. They voted for whi
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2 years ago
Points A(-2,3), B(-5,-4), and C(2,-1) form triangle ABC on a coordinate plane. What is the area of this triangle in square units
Veseljchak [2.6K]

1. Draw an accurate picture of the triangle in the coordinate axes, as shown in the attached picture.<span>

<span>2. Circumscribe a rectangle about the triangle, as shown in the picture. The coordinates of the points M, N, T are easily identifiable as shown in the picture.</span>

<span>3. The area of the triangle ABC is  The area of the rectangle - Area 1- Area 2- Area 3.</span>

Area 1 = 1/2(3*7)=21/2
Area 2 = 1/2(4*4)=1/2*16=8
<span>Area 3 = 1/2( 3*7)=21/2</span>

<span>Area 1+Area 2+Area 3=21/2+21/2+8=21+8=29 (units squared)</span>

<span>Area rectangle=  7*7=49 (units squared)</span>


<span>Answer: Area of triangle is 20 units squared.</span></span>

5 0
1 year ago
Read 2 more answers
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