Wednesday

January 28, 2015

January 28, 2015

Posted by **james** on Tuesday, January 22, 2013 at 10:15pm.

- precal -
**Reiny**, Tuesday, January 22, 2013 at 10:20pmFor half-life question, a good equation to use is

amount = starting value (1/2)^(t/k) where k is the half-life

so :

.35 = 1(1/2)^(t/2000) , t in years

.35 = (.5)^(t/2000

log .35 = log ( (.5)^(t/2000)

log .35 = (t/2000) log .5

t/2000 = log .35/log .5

t = 2000( log .35/log .5) = 3029.14

it would take appr 3029 years

**Answer this Question**

**Related Questions**

Calculus - The half life of a certain radioactive substance is 10 years. How ...

calculus - The rate at which an amount of a radioactive substance decays is ...

Math - A radioactive substance decays according to the formula Q(t) = Q0e−...

Math - A radioactive substance decays according to the formula Q(t) = Q0e−...

Math-Exponential Decay - A lab technician had 58 grams of a radioactive ...

Science - Radioactive substance decays so that after t years, the amount ...

Math - In 10 years, 25% of a radioactive substance decays. What is its half-life...

Algebra - In 10 years, 25% of a radioactive substance decays. What is its half-...

Calculus-derivatives - Verify if these are correct answers. 1. The derivative of...

Math - 1. If one wishes to accumulate a 30,000-fund in 5 years, how much should ...