The answer is
9n-2
d=9
1#=7
Answer:
Step-by-step explanation:
Present age of Barry = b
Present age of sister = s
Barry is 8 years older than his sister means if we subtract 8 from present age of Barry both will be of equal age
s=b-8 ............(1)
In 3 years means we have to add 3 in their present age
s+3=b+3
then
he will be twice as old as
2(s+3)=(b+3
2s+6=b+3
2s=b+3-6
2s=b-3...............(2)
Put the value of s from (1) to (2), we have
2(b-8)=b-3
2b-16=b-3
2b-b=-3+16
b=13
Put the value of b in (1)
s=13-8
s=5
Present age of Barry = b = 13
Present age of sister = s = 5
-9,-5, -1, 10 is the right order
Step-by-step explanation:
so, that means we want to find the time t (days) after which N = No/2
because "half-life" means the amount of time until half of the substance has disappeared (or transformed into something else).
so, we have
No/2 = No × e^(-0.1481×t)
No = 2× No × e^(-0.1481×t)
1 = 2×e^(‐0.1481×t)
1/2 = 0.5 = e^(-0.1481×t)
ln(0.5) = -0.1481×t
t = ln(0.5)/-0.1481 = 4.680264555... ≈ 4.7 days
