Question: A sample contains 68 grams of radioactive Bruinium. Sixteen days later, the sample had decayed to 47 grams.
1 answer:
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Answer:
2, 4
Step-by-step explanation:
Let there are two unknown consecutive pairs of even integers 2n and 2n+2.
If the sum of the reciprocals of those two integers is 3/4, then we can write,
1/2n +1/(2n+2) =3/4 ...... (1)
Solving this above equation we can check whether the integers exist or not.
Now, from equation (1) we get,
1/n +1/(n+1) =3/2
⇒
⇒4n +2 =3n²+3n
⇒3n²-n-2 =0
⇒ (n-1)(3n+2) =0
⇒ (n-1) =0 {Since if (3n+2) =0 then, n will be a negative fraction, which is not possible}
⇒ n=1
∴ 2n =2 and 2n+2 =4
Hence, the two integers are 2, 4. (Answer)
Answer:
The answer is
A. 529.66 ft²
Step-by-step explanation:
The picture of the composite figure is not given,
But find attached the figure.
The composite consists of two solid shapes
1. Cylinder
2. Rectangular prism
To solve for the total surface area of the composite
Let us solve for the total surface area of the cylinder
Given radius r= 4ft
Height h=5ft
A= πr²+2πrh-πr²
N/B we subtracted the second circular surface since it is joined to the rectangular prism
A= 3.142*4²+2(3.142)*4*5-3.142*4²
A= 50.272+125.68-50.272
A=125.68ft²
We proceed to find the area of the rectangular prism
We know that the prism has 6 sides
Hence area
A= 2(11*6)+ 2(8*6)+2(11*8)
A= 132+96+176
A= 404ft²
Hence total surface area is
404+125.68= 529.68ft²
