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2 years ago

Riley had $140.00. She gave Austin half of the money. She kept the rest. How much money does she have now?

Mathematics

2 answers:

Over [174]2 years ago

8 0

To solve this, you need to divide 140 by 2.This means that she gave $70 to Austin, and now has the remaining $70.00.

NISA [10]2 years ago

7 0

$70 is how much money she has left.

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We can solve this problem using separation of variables.

Then apply the initial conditions

EXPLANATION

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$\frac{dT}{T-a}=kdt$

Integrating both sides of the differential equation, we obtain;

$ln(T-a)=kt +c$

This natural logarithmic equation can be rewritten as;

$T-a=e^{kt +c}$

Applying the laws of exponents, we obtain,

$T-a=e^{kt}\times e^{c}$

$T-a=e^{c}e^{kt}$

We were given the initial conditions,

$T(0)=4$

Let us apply this condition to obtain;

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$-16=e^{c}$

Now our equation, becomes

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or

$T=a-16e^{kt}$

When we substitute a=20,
we obtain,

$T=20-16e^{kt}$

b) We were also given that,

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Let us apply this condition again to find k.

$8=20-16e^{5k}$

This implied

$-12=-16e^{5k}$

$\frac{-12}{-16}=e^{5k}$

$\frac{3}{4}=e^{5k}$

We take logarithm to base e of both sides,

$ln(\frac{3}{4})=5k$

This implies that,

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$k=-0.2877$

After 15 minutes, the temperature will be,

$T=20-16e^{-0.2877\times 15}$

$T=20-0.21376$

$T=19.786$

After 15 minutes, the temperature is approximately 20°C

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Answer:

Step-by-step explanation:

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Step-by-step explanation:

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2 years ago

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zheka24 [161]

Answer:

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Step-by-step explanation:

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Step-by-step explanation:

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