Equation for Half life :
A = a(0.5)^(t/h)
A is current amount, "a" is initial amount, h is halflife, t is time
5 = 40(0.5)^(t/1.3x10^9)
5/40 = (0.5)^(t/1.3x10^9)
take the log of both sides , power rule
Log(5/40) = (t/1.3x10^9) * Log(0.5)
(1.3x10^9) * Log(5/40) / Log(0.5) = t
3.9x10^9 years = t
And if you think about what a half life is, the time it take for the amount to reduce to half.
40/2 = 20
20/2 = 10
10/2 = 5
It went through 3 half-lifes
3 * 1.3x10^9 = 3.9x10^9 years
Answer:
Below
Explanation:
Salt solution, aka saline solution, is a homogeneous mixture. This means that the mixtures composition is completely uniform throughout. If you were to look at a saline solution, it would just look like plain water because the salt is dissolved (it looks the exact same in the entire mixture).
Something like bean soup would be an example of a heterogeneous mixture. You can see all the beans and vegetables as components of one mixture.
Hope this helps! Best of luck <3
