Element X decays radioactively with a half life of 14 minutes. If there are 230 grams of Element X, how long, to the nearest tenth of a minute, would it take the element to decay to 3 grams?

Brainliest please?

85.5 minutes

Step-by-step explanation:

The amount of an element that will remain after time t can be expressed as a function of initial amount N0, time t, and half life th as;

Nt = N0 × e^(-λt)

Where;

Decay constant λ = ln(2)/th, substituting into the equation;

Nt = N0 × e^(-ln(2)t/th)

We need to make t the subject of formula;

Nt/N0 = e^(-ln(2)t/th)

ln(Nt/N0) = -ln(2)t/th

t = ln(Nt/N0) ÷ -ln(2)/th

Given;

Initial amount N0 = 760g

Final amount Nt = 11 g

Half life th = 14 minutes

the nearest tenth of a minute, would it take the element to decay to 11 grams can be derived using the formula;

t = ln(Nt/N0) ÷ -ln(2)/th

Substituting the given values;

t = ln(11/760) ÷ -ln(2)/14

t = 85.5 minutes

(b) 240

step-by-step explanation:

first, we use the pythagorean formula using the given side lengths to find x. then we use x to find the side lengths. then we add the side lengths to find the perimeter.

pythagorean theorem formula:

a^2 + b^2 = c^2

(x - 20)^2 + (x - 40)^2 = x^2

x^2 - 40x + 400 + x^2 - 80x + 1600 = x^2

x^2 -120x + 2000 = 0

(x - 100)(x - 20) = 0

x - 100 = 0 or x - 20 = 0

x = 100 or x = 20

we see that the solution x = 20 must be discarded because it will give a negative side length and a side length of 0. the only valid solution is x = 100.

perimeter = sum of the lengths of the sides

perimeter = x + x - 20 + x - 40

perimeter = 3x - 60

replace x with 100.

perimeter = 3(100) - 60

perimeter = 300 - 60

perimeter = 240