Ageologist is studying two different rhyolite flows to determine if they were erupted at the same time.

9)rhyolite #1 has 50% of the parent isotope f remaining. how many half lives have occurred?
10)rhyolite #2 has 75% daughter g and 25% parent h. how many half lives has the rock gone through?
11)parent isotope f in the first question has a half life of 100 million years. use your answer from question 9 to determine the age of rhyolite#1.

It can be calculated using the equation:

 (1/2)ⁿ = x

x - decimal amount remaining, 

n - a number of half-lives.

x = 50% = 50/100 = 0.5

n = ?

(1/2)ⁿ = 0.5

log((1/2)ⁿ) = log(0.5)

n * log(1/2) = log(0.5)

n * log(0.5) = log(0.5)

n = log(0.5)/log(0.5)

n = 1

Q10. The answer is 2.

It can be calculated using the equation:

 (1/2)ⁿ = x

x - decimal amount remaining, 

n - a number of half-lives.

Rhyolite #2 has 25% of the parent H remaining:

x = 25% = 25/100 = 0.25

n = ?

(1/2)ⁿ = 0.25

log((1/2)ⁿ) = log(0.25)

n * log(1/2) = log(0.25)

n * log(0.5) = log(0.25)

n = log(0.25)/log(0.5)

n = -0.602 / - 0.301

n = 2

Q3. The answer is 100 million years.

A number of half-lives (n) is a quotient of total time elapsed (t) and length of half-life (H):

n = t/H

n = 1

t = ?

H = 100 000 000 years

n = t/H

t = n * H

t = 1 * 100 000 000 years

t = 100 000 000 years

answer: 20 percent

the fish culture has become a developing commercial practice in developing countries which is already prominent in developed countries of the world. the major fish protein demand is being supplemented in developing countries is   fishing to meet the needs of the growing population. therefore, in some developing nations, the percentage of animal protein from fish in the diet can be as high as 20 percent.