The half life
The half-life of a radioactive isotope is the time it takes for a quantity of the isotope to be reduced to half its initial mass. Starting with 145 grams of a radioactive isotope, how much will be left after 3 half-lives?
Did you find an error or inaccuracy? Feel free to write us. Thank you!
Thank you for submitting an example text correction or rephasing. We will review the example in a short time and work on the publish it.
Tips to related online calculators
Do you want to convert time units like minutes to seconds?
You need to know the following knowledge to solve this word math problem:
Related math problems and questions:
- Radioactive material
A radioactive material loses 10% of its mass each year. What proportion will be left there after n=6 years?
After 548 hours decreases the activity of a radioactive substance to 1/9 of the initial value. What is the half-life of the substance?
- Half life
Determine the half life of bismuth, when bismuth weight from the original weight of 32 g was only 2 grams in 242 minutes.
The crystal grows every month 1.2 permille of its mass. For how many months to grow a crystal from weight 177 g to 384 g?
- Suppose 2
Suppose that the half-life of a substance is 250 years. If there were initially 100 g of the substance, a. Give an exponential model for the situation b. How much will remain after 500 years?
- Geometric progression
In geometric progression, a1 = 7, q = 5. Find the condition for n to sum first n members is sn≤217.
- The city 2
Today lives 298000 citizens in the city. How many citizens can we expect in 8 years if their annual increase is 2.4%?
If you deposit 719 euros at the beginning of each year, how much money we have at 1.3% (compound) interest after 9 years?
- The town
The town population is 56000. It is decreasing by 2% every year. What will be the population of the town after 13 years?
We have a virus that lives one hour. Every half hour produce two child viruses. What will be the living population of the virus after 3.5 hours?
- Compound interest
Compound interest: Clara deposited CZK 100,000 in the bank with an annual interest rate of 1.5%. Both money and interest remain deposited in the bank. How many CZK will be in the bank after 3 years?
Apply for a $ 59000 loan, the loan repayment period is 8 years, the interest rate 7%. How much should I pay for every month (or every year if paid yearly). Example is for practise geometric progression and/or periodic payment for an annuity.
- Three members GP
The sum of three numbers in GP (geometric progression) is 21 and the sum of their squares is 189. Find the numbers.
One pull of wire is reduced its diameter by 14%. What will be the diameter of wire with diameter 19 mm over 10 pulls?
- Acid solution
By adding 250 grams of a 96% sulfuric acid solution to its 3% solution, we changed its initial concentration to 25%. How many grams of 3% of the acid was used for dilution?
- Curiosity factor
A blogger starts a new website, initially the number of the traffic is 293 due to their curiosity factor. The business owner estimated that the traffic will increase by 2,6% per week. What will be the number of it in week 5?.
- The work
The work was to be done by 150 workers. At the beginning of their work, their number reduced by 40, which increased the time of work by 5 and 1/3 of the schedule. How long did work take?