1. Answer: D. <span>A = 100 (1/2)^t/13.27
</span>Exponent equation formula would be an= a0( 1+r)^t
In this question, the radio isotopes will become half of its weight after the half-life. So, the ratio would be -0.5 (r= -0.5)
The halftime is 13.27 hours, so the time will be divided by that number. The result would look like this:
an= a0( 1+r)^t
an= a0( 1-0.5)^t/13.27
an= a0( 1/2)^t/13.27
2. Answer: x= 74°
<span>The ladder and the building will make a right triangle with the ladder as the hypotenuse.
The foot of the ladder is 2 feet from the building, so the adjacent side is 2ft.
It reaches a point 7 feet high on the building, so the opposite side is 7ft</span>
You can find the angle by using the tan equation
tan x= opposite / adjacent
tan x= 7/2= 3.5
x= 74°
<span>1 x + 1 y = 7 .............1
Total value
15 x + 28 y = 131 .............2
Eliminate y
multiply (1)by -28
Multiply (2) by 1
-28 x -28 y = -196
15 x + 28 y = 131
Add the two equations
-13 x = -65
/ -13
x = 5
plug value of x in (1)
1 x + 1 y = 7
5 + y = 7
y = 7 -5
y = 2
y = 2
x= 5 plain shirts
y= 2 fancy shirts </span>
Answer:
8.5
Step-by-step explanation:
For continuous compounding, the account value formula is ...
A = Pe^(rt)
where P is the invested amount, r is the annual interest rate, and t is the number of years. We want to find t when ...
3550 = 2400e^(.046t)
ln(355/240) = 0.046t
t = ln(355/240)/0.046 ≈ 8.5
It will take 8.5 years for the value to reach $3550.
