Answer:
The half-life of the radioactive substance is 135.9 hours.
Step-by-step explanation:
The rate of decay is proportional to the amount of the substance present at time t
This means that the amount of the substance can be modeled by the following differential equation:

Which has the following solution:

In which Q(t) is the amount after t hours, Q(0) is the initial amount and r is the decay rate.
After 6 hours the mass had decreased by 3%.
This means that
. We use this to find r.







So

Determine the half-life of the radioactive substance.
This is t for which Q(t) = 0.5Q(0). So







The half-life of the radioactive substance is 135.9 hours.
In this big ol' word problem, this is just an instance of basic multiplication/division.
If it takes it 1 hour for 3 meters...
12 ÷ 3 = 4.
It would take 4 hours for the water level to change to 12 meters.
Answer:
5,7,-1
Step-by-step explanation:
5) -5+5<7=0<7 TRUE
7)-7+5<7=--2<7 TRUE
-1)-(-1)+5<7=6<7 TRUE
-3)-(-3)+5<7=8<7 FALSE
-2)-(-2)+5<7=7<7 FALSE
A straight line is 180° and this is less than that but it’s more than 90°, 105° is close to 90 and this is a bit bigger so your best estimate is
B.) 180°