Answer:
It will take 25.6 years for the mass of the sample to reach 400 grams.
Step-by-step explanation:
Element X is a radioactive isotope such that every 25 years, its mass decreases by half.
This means that the amount of the substance after t years can be modeled by a function in the following format:
In which A(0) is the initial amount.
Initial mass of a sample of Element X is 910 grams.
This means that
So
How long would it be until the mass of the sample reached 400 grams?
This is t for which
So
It will take 25.6 years for the mass of the sample to reach 400 grams.
Answer: 400 520<15x+400x 15x+400>520
Step-by-step explanation:
Answer:
630
Step-by-step explanation:
The sum of an arithmetic sequence is given by ...
Sn = n(2a1 +(n-1)d)/2
For the sequence of numbers of bales, we have ...
a1 = 123, d = -11, n = 7
so the total number of bales in 7 trips around the field is ...
S7 = 7(2·123 +6(-11))/2 = 630
The total number of bales made is about 630.
_____
123 + 112 + 101 + 90 + 79 + 68 + 57 = 630
0.147058824 but you might just want to use your calculator.