Answer:
74 days
Step-by-step explanation:
The computation is shown below;
The proportion that remains left after d days is
p = (1/2)^(d ÷ 100)
In the case when the proportion is 60%
So,
0.60 = 0.50^(d ÷ 100)
Now
log(.60) = (d ÷ 100)log(.50)
100·log(.60) ÷ log(.50) = d = 74 days
Answer: 
Step-by-step explanation:
We apply the formula
.
Note that
. Take
and
in the formula above to get

Then the value of this expression is 
We can use the cosine addition formula again to simplify further. Decompose the fraction in the argument as:

Applying the formula with
and
we obtain

We conclude that this expression has the value 
Answer:
D 21
Step-by-step explanation: x/7 = 3
isolate x by multiplyig both sides by 7: (7)(x/7) = (3)(7)
x = 21
Answer:
?
Step-by-step explanation: