Answer:
x = 5
Step-by-step explanation:
The opposite sides of a rectangle are equal , then perimeter
2(- 2x - 6) + 2(4x + 4) = 16 ← distribute parenthesis and simplify left side
- 4x - 12 + 8x + 8 = 16
4x - 4 = 16 ( add 4 to both sides )
4x = 20 ( divide both sides by 4 )
x = 5
Answer:
The substance half-life is of 4.98 days.
Step-by-step explanation:
Equation for an amount of a decaying substance:
The equation for the amount of a substance that decay exponentially has the following format:
In which k is the decay rate, as a decimal.
k-value of 0.1392.
This means that:
Find the substance's half life, in days.
This is t for which 
. So
The substance half-life is of 4.98 days.
The answer to this question is:
83/100
Answer:
56.25
Step-by-step explanation:
Answer:
60 km/h
Step-by-step explanation:
Let us use the x to represent the speed of the car since it is the smaller value.
Then, the distance covered by the car is 4x since was going 4 kph.
The distance covered by the train is (x+5) times 7 or 7x+35.
We know that the total distance covered is 640 km.
Using this information, we can set up the equation 4x+7x+35=640.
By subtracting both sides by 35 and combining the x's, we get a new equation of 11x=605.
After this, we divide both sides by 11 and get x=55.
Lastly, we add 5 to 55 since the train is 5 km faster than the car and that x stood for the car.
Train=60 km/h
