The half life of radium is 1690 years. If 10 grams are present now, how much will be present in 50 years?

Kala purchased a prepaid phone card for $15. Long distance calls cost $12 a minute using this card. Kala Use her card only once

irina [24]

Kala call lasted for 0.36 minutes

<em><u>Solution:</u></em>

Given that Kala purchased a prepaid phone card for $15

Long distance calls cost $12 a minute using this card.

If the remaining credit on her card is $10.68

To find: Number of minutes her call lasted

Let "x" be the number of minutes her call lasted

Cost of 1 minute = $ 12

Total balance = $15

Remaining balance = $ 10.68

So we can frame a equation as:

Total balance = Remaining balance + Cost of 1 minute x number of minutes her call lasted

$15 = 10.68 + 12 \times x\\\\15 - 10.68 = 12x\\\\4.32 = 12x\\\\x = 0.36$

So her call lasted for 0.36 minutes

4 0

2 years ago

For what values of $x$ is $$\frac{x^2 + x + 3}{2x^2 + x - 6} \ge 0?$$ note: be thorough and explain why all points in your answe

Rus_ich [418]

To solve the inequality $\frac{x^2+x+3}{2x^2+x-6}\ge \:0$

$\mathrm{Factor\:the\:left\:hand\:side\:}\frac{x^2+x+3}{2x^2+x-6}:$

The numerator $x^2+x+3$ is not factorizable.

so factor the denominator $2x^2+x-6$ :

$2x^2+x-6=\left(2x^2-3x\right)+\left(4x-6\right)=x\left(2x-3\right)+2\left(2x-3\right)\\ \mathrm{Factor\:out\:}x\mathrm{\:from\:}2x^2-3x\mathrm{:\quad }x\left(2x-3\right)\\ \mathrm{Factor\:out\:}2\mathrm{\:from\:}4x-6\mathrm{:\quad }2\left(2x-3\right)\\$

Now take $\mathrm{Factor\:out\:common\:term\:}\left(2x-3\right)$

Then we get factor of the denominator as $\left(2x-3\right)\left(x+2\right)$

Thus $\frac{x^2+x+3}{2x^2+x-6}=\frac{x^2+x+3}{\left(x+2\right)\left(2x-3\right)}$

Now $\mathrm{Compute\:the\:signs\:of\:the\:factors\:of\:}\frac{x^2+x+3}{\left(x+2\right)\left(2x-3\right)}\\$

Signs of $x^2+x+3>0$

$\mathrm{Choosing\:ranges\:that\:satisfy\:the\:required\:condition:}\:\ge \:\:0$

$x\frac{3}{2}$ is the required solution of the given inequality.

5 0

2 years ago

Read 2 more answers

Tony's taking cookies to a bake sale. He already made 70 cookies on Monday, and wants to make more on Tuesday. His plan allows h

kotegsom [21]

70+14 x 7 =168 :-] :-] :-]

6 0

2 years ago

What is the anwser answer to 34% into a fraction?

Lelechka [254]

The answer would be 34/100 or 17/50 if reduced .

7 0

2 years ago

Read 2 more answers

Which of the following functions is graphed below?

Vladimir [108]

Answer:

Step-by-step explanation:

The answer is D because the parabola is an empty circle and is positive which would mean its greater than 1 and the line has a solid point and is negative which means less than or equal to.

5 0

2 years ago