10% off of 199.99 is 179.99
100% - 10% = 90% The 90% is how much you are going to pay.
90% into decimal form is 0.9
So you can do 199.99 x 0.9 = $179.99
Answer:
x=19
Step-by-step explanation:
50 - 3x = x -26
50-3x-50=x-26-50
-3x=x-76
-3x-x=x-76-x
-4x= -76
x= -76/-4
x=19
Answer:
9. The scale factor is 1.5.
10. scale factor = 0.75
the missing side is 9m
Step-by-step explanation:
9. 3/2 = 1.5
9/6 = 1.5
6/4 = 1.5
10. 12/16 = 0.75
12*0.75 = 9
Answer:
a) The half life of the substance is 22.76 years.
b) 5.34 years for the sample to decay to 85% of its original amount
Step-by-step explanation:
The amount of the radioactive substance after t years is modeled by the following equation:

In which P(0) is the initial amount and r is the decay rate.
A sample of a radioactive substance decayed to 97% of its original amount after a year.
This means that:

Then



So

(a) What is the half-life of the substance?
This is t for which P(t) = 0.5P(0). So







The half life of the substance is 22.76 years.
(b) How long would it take the sample to decay to 85% of its original amount?
This is t for which P(t) = 0.85P(0). So







5.34 years for the sample to decay to 85% of its original amount