# 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?

Correct result:

m3 =  18.125 g

#### Solution: We would be pleased if you find an error in the word problem, spelling mistakes, or inaccuracies and send it to us. Thank you! Tips to related online calculators
Do you want to convert time units like minutes to seconds?

## Next similar math problems:

• Tenth member Calculate the tenth member of geometric sequence when given: a1=1/2 and q=2
• Six terms Find the first six terms of the sequence a1 = -3, an = 2 * an-1
• Geometric progression 2 There is geometric sequence with a1=5.7 and quotient q=-2.5. Calculate a17.
• Terms of GP What is the 6th term of the GP 9, 81, 729,. .. ?
• Equation How many real roots has equation ? ?
• Five members Write first 5 members geometric sequence and determine whether it is increasing or decreasing: a1 = 3 q = -2
• GP - 8 items Determine the first eight members of a geometric progression if a9=512, q=2
• Geometric sequence 4 It is given geometric sequence a3 = 7 and a12 = 3. Calculate s23 (= sum of the first 23 members of the sequence).
• Five harvests In the seed company, they know that, out of 100 grains of a new variety, they get an average of 2000 grains after harvest. Approximately how many grains do they get out of 100 grains after five harvests?
• Quotient Determine the quotient and the second member of the geometric progression where a3=10, a1+a2=-1,6 a1-a2=2,4.
• Common ratio If 200 units of a commodity are consumed in a first year, and if the annual rate of increase in consumption is 5% (a) what amount is consumed in the 8th year; (b) in the first 15 years?
• The crime The crime rate of a certain city is increasing by exactly 7% each year. If there were 600 crimes in the year 1990 and the crime rate remains constant each year, determine the approximate number of crimes in the year 2025.
• Population What is the population of the city with 3% annual growth, if in 10 years the city will have 60,000 residents?
• Compound interest 3 After 8 years, what is the total amount of a compound interest investment of $25,000 at 3% interest, compounded quarterly? (interest is now dream - in the year 2019) • Retirement annuity How much will it cost to purchase a two-level retirement annuity that will pay$2000 at the end of every month for the first 10 years, and \$3000 per month for the next 15 years? Assume that the payment represent a rate of return to the person receiving th
• The city At the end of 2010 the city had 248000 residents. The population increased by 2.5% each year. What is the population at the end of 2013?
• The city 2 Today lives 167000 citizens in city. How many citizens can we expect in 11 years if their annual increase is 1%?