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3 years ago

PLEASE HELP ME AND PLEASE BE RIGHT I ALREADY HAVE AN 80 :(

Mathematics

1 answer:

ELEN [110]3 years ago

6 0

Answer:

Step-by-step explanation:

When calculating the area of a parallelogram, use the formula A = l*h where length is the longest length and h is the perpendicular height of the shape. For this parallelogram, substitute l = 14 and h = 8.

A = l*w = 14*8 = 112

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Jan's age is 3 less than twice trents age. The sum of their ages is 30

wel

Answer:

jan is 8

Step-by-step explanation:

8 0

3 years ago

According to one cosmological theory, there were equal amounts of the two uranium isotopes 235U and 238U at the creation of the

FromTheMoon [43]

Answer:

6 billion years.

Step-by-step explanation:

According to the decay law, the amount of the radioactive substance that decays is proportional to each instant to the amount of substance present. Let $P(t)$ be the amount of $^{235}U$ and $Q(t)$ be the amount of $^{238}U$ after $t$ years.

Then, we obtain two differential equations

$\frac{dP}{dt} = -k_1P \quad \frac{dQ}{dt} = -k_2Q$

where $k_1$ and $k_2$ are proportionality constants and the minus signs denotes decay.

Rearranging terms in the equations gives

$\frac{dP}{P} = -k_1dt \quad \frac{dQ}{Q} = -k_2dt$

Now, the variables are separated, $P$ and $Q$ appear only on the left, and $t$ appears only on the right, so that we can integrate both sides.

$\int \frac{dP}{P} = -k_1 \int dt \quad \int \frac{dQ}{Q} = -k_2\int dt$

which yields

$\ln |P| = -k_1t + c_1 \quad \ln |Q| = -k_2t + c_2$ ,

where $c_1$ and $c_2$ are constants of integration.

By taking exponents, we obtain

$e^{\ln |P|} = e^{-k_1t + c_1} \quad e^{\ln |Q|} = e^{-k_12t + c_2}$

Hence,

$P = C_1e^{-k_1t} \quad Q = C_2e^{-k_2t}$ ,

where $C_1 := \pm e^{c_1}$ and $C_2 := \pm e^{c_2}$ .

Since the amounts of the uranium isotopes were the same initially, we obtain the initial condition

$P(0) = Q(0) = C$

Substituting 0 for $P$ in the general solution gives

$C = P(0) = C_1 e^0 \implies C= C_1$

Similarly, we obtain $C = C_2$ and

$P = Ce^{-k_1t} \quad Q = Ce^{-k_2t}$

The relation between the decay constant $k$ and the half-life is given by

$\tau = \frac{\ln 2}{k}$

We can use this fact to determine the numeric values of the decay constants $k_1$ and $k_2$ . Thus,

$4.51 \times 10^9 = \frac{\ln 2}{k_1} \implies k_1 = \frac{\ln 2}{4.51 \times 10^9}$

and

$7.10 \times 10^8 = \frac{\ln 2}{k_2} \implies k_2 = \frac{\ln 2}{7.10 \times 10^8}$

Therefore,

$P = Ce^{-\frac{\ln 2}{4.51 \times 10^9}t} \quad Q = Ce^{-k_2 = \frac{\ln 2}{7.10 \times 10^8}t}$

We have that

$\frac{P(t)}{Q(t)} = 137.7$

Hence,

$\frac{Ce^{-\frac{\ln 2}{4.51 \times 10^9}t} }{Ce^{-k_2 = \frac{\ln 2}{7.10 \times 10^8}t}} = 137.7$

Solving for $t$ yields $t \approx 6 \times 10^9$ , which means that the age of the universe is about 6 billion years.

5 0

3 years ago

Evaluate 3(5 - 8) - 7

Salsk061 [2.6K]

Answer:

-16

Step-by-step explanation:

3*5=15

3*8=24

15-24= -9

-9-7=-16

7 0

3 years ago

A sociologist wants to know the opinions of employed adult women about government funding for day care. The women were asked to

Zarrin [17]

Answer:

The correct option is C 20.1%.

Step-by-step explanation:

The probability distribution chart representing the opinions of employed adult women about government funding for day care is as follows:

Rating (<em>X</em>) Probability (<em>p</em>)

1 0.110

2 0.206

3 0.464

4 0.201

5 0.119

The ratings are defined as follows:

1: too little

2: helpful but not enough

3: make a difference but insufficient

4: sufficient

5: generous

The probability of women who think that the support is sufficient is, 0.201.

The percentage is: 0.201 × 100 = 20.1%

Thus, the percentage of women who think that the support is sufficient is 20.1%.

The correct option is C.

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3 years ago

During a dry year, the reservoir level dropped 512 feet. The next year the level rose 314 feet. Which expression shows the total

tia_tia [17]

Answer:

You will be hot as shet

Step-by-step explanation:

5 0

3 years ago