Answer:
It will take 7 years ( approx )
Step-by-step explanation:
Given equation that shows the amount of the substance after t years,
Where,
= Initial amount of the substance,
If the half life of the substance is 19 years,
Then if t = 19, amount of the substance = 
,
i.e.
Taking ln both sides,
Now, if the substance to decay to 78% of its original amount,
Then 
Again taking ln both sides,
Hence, approximately the substance would be 78% of its initial value after 7 years.
Answer:
g=-7x-1/x
Step-by-step explanation:
Answer:
We can set up a system of equations.
x + y = 111
0.25x + 0.10y = 18.30
x + y = 111
Subtract 'y' to both sides:
x = -y + 111
Plug in '-y + 111' for 'x' in the 2nd equation:
0.25(-y + 111) + 0.10y = 18.30
Distribute 0.25 into the parenthesis:
-0.25y + 27.75 + 0.10y = 18.30
Combine like terms:
-0.15y + 27.75 = 18.30
Subtract 27.75 to both sides:
-0.15y = -9.45
Divide -0.15 to both sides:
y = 63
Plug this back into any of the two equations to find the 'x' value.
x + y = 111
x + 63 = 111
Subtract 63 to both sides:
x = 48
So there are 48 quarters and 63 dimes.
Step-by-step explanation:
Hope This Helps!
Option 3 (1/4 x 60) since 59 is close to 60 and 25% can be rewritten as 1/4
Answer:
Step-by-step explanation:
That would be 8 x 3. It would help because 24/8 = 3.
