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3 years ago

11

Element X is a radioactive isotope such that every 13 years, its mass decreases by half. Given that the initial mass of a sample

of Element X is 60 grams, how much of the element would remain after 30 years, to the nearest whole number?

1 answer:

Nana76 [90]3 years ago

8 0

Answer:

2,325 grams !

Step-by-step explanation:

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The globe used in social studies class has a diameter of 42 centimeters, What is its volume

Leni [432]

Answer:

Step-by-step explanation: pi r^2

so 42/2 equals 21 radius

volume=22/7 x 21^2

v=1385

5 0

3 years ago

Read 2 more answers

A circular jogging track forms the edge of a circular lake that has a diameter of 2 miles. Johanna walked once around the track

harkovskaia [24]

Answer:

C. 2.0 < t < 2.5

Step-by-step explanation:

time = distance / speed

The circumference of the lake is given by ...

C = πd = 2π miles ≈ 6.28 miles

Then Johanna's time is ...

(6.28 mi)/(3 mi/h) ≈ 2.09 h

This time is in the interval (2, 2.5), so matches choice C.

___

<em>Alternate solution</em>

If we take pi to be 3, then this boils down to ...

2×3/3 = 2 . . . hours

Pi is on the order of 5% more than 3, so her time will be on the order of 5% more than 2 hours, or just above 2, but not as great as 2.5 hours. This sort of estimating can get you to the correct answer without a calculator.

6 0

3 years ago

the value of y varies directly proportional to the value of x. When x = 50, the value of y= 2500. What is the value of y, when x

USPshnik [31]

Answer:

The required value of y is 4800

4 0

3 years ago

Solve for x. 89(54x−36)+2=−34(−40+16x)+90x

krok68 [10]

Eliminate parentheses using the distributive property.
4806x -3204 +2 = 1360 -544x +90x
5260x = 4562
x = 4562/5260
x = 2281/2630

7 0

3 years ago

Find the final amount. $4000 invested at 11% APR compounded quarterly for 5 years The final amount is $ nothing. (Do not rou

Angelina_Jolie [31]

<h3>The final amount is $ 6881.71</h3>

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

<em><u>The formula for compound interest, including principal sum, is:</u></em>

$A = p(1 + \frac{r}{n})^{nt}$

Where,

A = the future value of the investment

P = the principal investment amount\

r = the annual interest rate in decimal

n = the number of times that interest is compounded per unit t

t = the time the money is invested

From given,

p = 4000

t = 5

$r = 11 \% = \frac{11}{100} = 0.11$

n = 4 ( compounded quarterly )

<em><u>Substituting the values in formula,</u></em>

$A = 4000(1 + \frac{0.11}{4})^{4 \times 5}\\\\ A = 4000( 1.0275)^{20}\\\\A = 4000 \times 1.720428\\\\A = 6881.7137 \approx 6881.71$

Thus the final amount is $ 6881.71

5 0

3 years ago