Answer:
8
Step-by-step explanation:
Answer: 4 years
Step-by-step explanation:
A(0) has to be amount at start. Assume that's 5mg
Then A(t) = 5×(0.5)^(0.25t) = 5×2^(-t/4),
(also known as 5 exp(-λ t) with λ = ln(2)/4, incidentally).
We need to such that A(t) = 2.5mg, or 2^(-t/4) is 1/2, which happens when -t/4 is -1, or t is 4.
Answer:
m + n = 15
m - 3 = n
The numbers are 9 and 6
Step-by-step explanation:
From the question,
The sum of two numbers is fifteen; the first number is m and the second number is n. To translate to a system of equations, we can write that
m + n = 15 ..... (1)
Also, from the question,
One number is three less than the other,
Also, to translate to a system of equations, we can write that
m - 3 = n ...... (2)
If desired, we can determine m and n
From equation (1)
m + n = 15
Then,
m = 15 - n ...... (3)
Put the value of m in equation (3) into equation (2)
m - 3 = n
Then
15 - n - 3 = n
15 - 3 = n + n
12 = 2n
n = 12/2
∴ n = 6
For m, put the value of n into equation 3
m = 15 - n
m = 15 - 6
m = 9
∴ m = 9 and n = 6
Hence, the numbers are 9 and 6
