Answer:
18 minutes
Step-by-step explanation:
A = A₀ (½)^(t / T)
where A is the final amount,
A₀ is the initial amount,
t is the time,
and T is the half life.
A = 140 when t = 10. Solve for the half life:
140 = 700 (½)^(10 / T)
0.2 = ½^(10 / T)
log 0.2 = (10 / T) log 0.5
10 / T = 2.32
T = 4.31
When A = 40, t is:
40 = 700 (½)^(t / 4.31)
0.057 = ½^(t / 4.31)
log 0.057 = (t / 4.31) log 0.5
t / 4.31 = 4.13
t = 17.8
Rounded to the nearest whole number, it takes 18 minutes.
Answer:
A
Step-by-step explanation:
because there variables represent 1 so 1 cant be bigger than one and the other two have real equations
If you get behind on a payment in messes you up
If the sum of two numbers is x
Then the equation is like this:
a+b = x
Then it says one of the number is 12. Change either a or b into 12
12 + b =x
If we want to find the other number, we need the make it into the subject
b = x - 12
Hope that help.