Radium-226 has a half-life of 1660 years. How many years does it take a radium sample to decay to 55% of the original amount? Round your answer to the nearest year.

1432 years

Step-by-step explanation:

A(t) = I(0.5)^t/t1/2

Where t1/2 = half life = 1660

Final amount, A(t) = 0.55 of its original amount =. 0.55I

Hence, we have

0.55I = I(0.5)^t/1660

Take the log of both sides

Log(0.55) = log(0.5)^t/1660

t/1660 = log(0.55) / log(0.5)

t/1660 = 0.8624964

t = 0.8624964 * 1660

t = 1431.7441

t = 1432(nearest whole number)

We can do the elimination method to find the solution for this problem. The elimination method involves adding the two equations together to get rid of a like term.

x + 2y = 7
+ x - 2y = -1
—————————
2x = 6

Now that we eliminated 2y because they cancel out, we are left with 2x = 6. Divide both sides by 2 in order to get x.

The answer is: x = 3.

Now that we know the numerical value of x, all we have to do is plug x into either system of equation in order to find the numerical value of y.

x + 2y = 7

3 + 2y = 7

2y = 4

y = 2

The solution to the problem is (3, 2).