25x=65
We divide 25 to cancel it out.
65/25=2.6
I would assume 3, because 2.6 is 3 when rounded up.
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hope it helps
Answer:
30 CDs and 10 Videos were sold.
Step-by-step explanation:
Given that a used book store also started selling used CDs and videos. In the first week, the store sold 40 used CDs and videos, at 4.00 per CD and 6.00 per video.
The sales for both CDs and videos totaled to 180.00.
Let CDs be x and Videos be y
Then we have x+y =3040
and 4x+6y = 180
Two simultaneous equations in two variables and can be solved by elimination method
multiply I equation by 4 and subtract from II.
2y = 20
y =10
x = 30
30 CDs and 10 Videos were sold.
Answer:
The half-life of the radioactive substance is 135.9 hours.
Step-by-step explanation:
The rate of decay is proportional to the amount of the substance present at time t
This means that the amount of the substance can be modeled by the following differential equation:
Which has the following solution:
In which Q(t) is the amount after t hours, Q(0) is the initial amount and r is the decay rate.
After 6 hours the mass had decreased by 3%.
This means that . We use this to find r.
So
Determine the half-life of the radioactive substance.
This is t for which Q(t) = 0.5Q(0). So
The half-life of the radioactive substance is 135.9 hours.
F(x) = x/2
g(x) = x - 3
f(8) = 8/2 = 4
g(f(x)) = 4 - 3 = 1
Answer g(f(8)) = 1