# Radioactivity

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?

**Result****Leave us a comment of example and its solution (i.e. if it is still somewhat unclear...):**

**Showing 0 comments:**

**Be the first to comment!**

#### To solve this verbal math problem are needed these knowledge from mathematics:

## Next similar examples:

- Theorem prove

We want to prove the sentence: If the natural number n is divisible by six, then n is divisible by three. From what assumption we started? - Log

if ?, what is b? - The city 3

The city has 22,000 residents. How long it is expected to have 25,000 residents if the average annual population growth is 1.4%? - Exponential equation

In the set R solve the equation: ? - Logarithm

Determine the number whose decimal logarithm is -3.8. - Intercept with axis

F(x)=log(x+4)-2, what is the x intercept - Water lilies

Water lilies are growing on the pond and their number is doubled every day. The whole layer is covered in 12 days. How many days will it cover 8 layers? - Coordinate

Determine missing coordinate of the point M [x, 120] of the graph of the function f bv rule: y = 5^{x} - Sequence

Calculate what member of the sequence specified by ? has value 86. - Exponential equation

Solve exponential equation (in real numbers): 9^{8x-2}=9 - Powers 3

2 to the power of n divided by 4 to the power of -3 equal 4. What is the vaule of n? - Computer revolution

When we started playing with computers, the first processor, which I remember was the Intel 8080 from 1974, with the performance of 0.5 MIPS. Calculate how much percent a year rose CPU performance when Intel 486DX from 1992 has 54 MIPS. What - Compound interest

Calculate time when deposit in the bank with interest 2.5% p.a. doubles. - Car value

The car loses value 15% every year. Determine a time (in years) when the price will be halved. - An investment

How long will it take for an investment to double at a simple interest rate of 5.10% p. A. ? Express the answer in years and months, rounded up to the next month. - Sequence

Between numbers 1 and 53 insert n members of the arithmetic sequence that its sum is 702. - Population

What is the population of the city with 3% annual growth, if in 10 years the city will have 60,000 residents?