Suppose that a mineral body formed in an ancient cataclysm—perhaps the formation of the earth itself— originally contained the uranium isotope 238u (which has a half-life of 4: 51 109 years) but no lead, the end product of the radioactive decay of 238u. if today the ratio of 238u atoms to lead atoms in the mineral body is 0.9, when did the cataclysm occur?

The cataclysm occured 6.85x10^8 years ago.

Step-by-step explanation:

Considering that the half-life is 4.51x10^9 years, the first step to solve this problem is finding k by the formula k=ln(0.5)/t(half-life). This constant of decay can then be replaced in the N=No x e^(-kt). Since the problem states that the ratio N/No = 0.9, solving the formula for t will give you a time of 6.85x10^8 years. The question was when did the cataclysm occured so it is safe to say that it was about 685,000,000 years ago.

m a t h w a y. c o m

step-by-step explanation:

so firstly, we need to isolate the y variables to be able to solve these inequalities. firstly, add 0.5x on both sides of the first inequality and subtract 1.5x on both sides of the second inequality:

now since the slope is positive for the first inequality, this means that the line going upwards belongs to the first inequality, and the line going downwards belongs to the second inequality.

next, since y ≥ in the first inequality, this means that the shaded region will be above the first inequality's line, thus shading regions a and b.

next, since y ≤ in the second inequality, this means that the shaded region is going to be below this line, thus shading regions a and c.

since both lines shade region a, this means that region a is the solution.

step-by-step explanation:

mark brainliest!