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3 years ago

7

A big group of people are taking the train home for Christmas. 19 people get off the train in Brooklyn, 17 people then get on. N

ow there are 63 people on the train. How many were there to begin with?

1 answer:

Lana71 [14]3 years ago

5 0

There was 65 people to begin the train ride

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Please Help me with the last three questions!<br> It is urgent!

MrMuchimi

Answers:
1. X= 0
2. X= 0
3. X=3

You can use this method to solve them step by step, hope it will help!

8 0

3 years ago

A bacteria culture starts with 12,000 bacteria and the number doubles every 50 minutes.

Vlada [557]

Answer:

a) $y=12000(2)^{\frac{t}{50}}$

b) Approx. 27,569 bacteria

c) About 103 minutes

Step-by-step explanation:

a)

This will follow exponential modelling with form of equation shown below:

$y=Ab^{\frac{t}{n}}$

Where

A is the initial amount (here, 12000)

b is the growth factor (double, so growth factor is "2")

n is the number of minutes in which it doubles, so n = 50

Substituting, we get our formula:

$y=Ab^{\frac{t}{n}}\\y=12000(2)^{\frac{t}{50}}$

b)

To get number of bacteria after 1 hour, we have to plug in the time into "t" of the formula we wrote earlier.

Remember, t is in minutes, so

1 hour = 60 minutes

t = 60

Substituting, we get:

$y=12000(2)^{\frac{t}{50}}\\y=12000(2)^{\frac{60}{50}}\\y=12000(2)^{\frac{6}{5}}\\y=27,568.76$

The number of bacteria after 1 hour would approximate be <u>27,569 bacteria</u>

<u></u>

c)

To get TIME to go to 50,000 bacteria, we will substitute 50,000 into "y" of the equation and solve the equation using natural logarithms to get t. Shown below:

$y=12000(2)^{\frac{t}{50}}\\50,000=12,000(2)^{\frac{t}{50}}\\4.17=2^{\frac{t}{50}}\\Ln(4.17)=Ln(2^{\frac{t}{50}})\\Ln(4.17)=\frac{t}{50}*Ln(2)\\\frac{t}{50}=\frac{Ln(4.17)}{Ln(2)}\\\frac{t}{50}=2.06\\t=103$

After about 103 minutes, there will be 50,000 bacteria

4 0

3 years ago

How do i solve this question

alex41 [277]

Answer:

18.18

Step-by-step explanation:

total sum of angle of quadrilateral is 360

70+60+ 7x-4+4x-3=360

160-7 +11x =360

153 +11x =360

11x=360-153

x=207/11

x=18.18

7 0

2 years ago

IrinaK [193]

Answer:

sorry for points

Step-by-step explanation:

6 0

2 years ago

What is the value of x in the following equation?<br> 4r +6<br> + 3 = -6<br> -6<br> -3

zhuklara [117]

Answer:

x = -6

Step-by-step explanation:

Solve for x:

(4 x + 6)/2 + 3 = -6

Hint: | Put the fractions in (4 x + 6)/2 + 3 over a common denominator.

Put each term in (4 x + 6)/2 + 3 over the common denominator 2: (4 x + 6)/2 + 3 = 6/2 + (4 x + 6)/2:

6/2 + (4 x + 6)/2 = -6

Hint: | Combine 6/2 + (4 x + 6)/2 into a single fraction.

6/2 + (4 x + 6)/2 = ((4 x + 6) + 6)/2:

(4 x + 6 + 6)/2 = -6

Hint: | Add the numbers in 4 x + 6 + 6 together.

Add like terms. 6 + 6 = 12:

(4 x + 12)/2 = -6

Hint: | Multiply both sides by a constant to simplify the equation.

Multiply both sides of (4 x + 12)/2 = -6 by 2:

(2 (4 x + 12))/2 = -6×2

Hint: | Cancel common terms in the numerator and denominator of (2 (4 x + 12))/2.

(2 (4 x + 12))/2 = 2/2×(4 x + 12) = 4 x + 12:

4 x + 12 = -6×2

Hint: | Multiply 2 and -6 together.

2 (-6) = -12:

4 x + 12 = -12

Hint: | Isolate terms with x to the left hand side.

Subtract 12 from both sides:

4 x + (12 - 12) = -12 - 12

Hint: | Look for the difference of two identical terms.

12 - 12 = 0:

4 x = -12 - 12

Hint: | Evaluate -12 - 12.

-12 - 12 = -24:

4 x = -24

Hint: | Divide both sides by a constant to simplify the equation.

Divide both sides of 4 x = -24 by 4:

(4 x)/4 = (-24)/4

Hint: | Any nonzero number divided by itself is one.

4/4 = 1:

x = (-24)/4

Hint: | Reduce (-24)/4 to lowest terms. Start by finding the GCD of -24 and 4.

The gcd of -24 and 4 is 4, so (-24)/4 = (4 (-6))/(4×1) = 4/4×-6 = -6:

Answer: x = -6

4 0

2 years ago