Let r be the decay rate (time in minutes) 17 = 20 e^(5r) 0.85 = e^(5r) ln 0.85 = 5r similarly, ln 0.5 = hr ... where h is the half-life, so dividing the 2 equations, ln 0.85 / ln 0.50 = 5r / hr = 5/h h = 5 ln 0.50 / ln 0.85 h = 21.3 min b) 1/20 = 0.05, so ln 0.85 = 5r ln 0.05 = tr t = 5 ln 0.05 / ln 0.85 t = 92.2 min
Answer: 0.5
Step-by-step explanation:
Since this is a equilateral triangle all angles are equal to each other. All angles in a triangle always add up to 180 degrees.
So you would set up your equation like so
3(7x - 3) = 180
The 3 outside the parenthesis resembles the 3 angles.
You equal the equation to 180 since all the angles in a triangle = 180
So distribute the 3
21x - 9 = 180
Add 9 to both sides
21x = 189
Divide 21 on both sides
x = 9
Refer to the diagram shown below.
The velocity of the person on the walkway relative to the ground is the velocity of the walkway (relative to the ground) plus the velocity of the person relative to the walkway.
It is
1.0 + 0.5 = 1.5 m/s
The person on the ground moves at - 0.2 m/s, which is in the opposite direction to that of the walkway and the person on the walkway.
Therefore the velocity of the person on the walkway relative to the person on the ground is
105 - (-0.2) = 1.7 m/s
Answer: 1.7 m/s