Answer:
19.3 years
Step-by-step explanation:
Given that the initial mass of a sample of Element X is 100 grams,
The formula is given as:
N(t) = No × (1/2) ^t/t½
Element X is a radioactive isotope such that every 30 years, its mass decreases by half.
N(t) = Mass after time (t)
No = Initial mass = 100 grams
t½ = Half life = 30 grams
N(t) = 100 × (1/2) ^t/30
How long would it be until the mass of the sample reached 64 grams, to the nearest tenth of a year?
This means we are to find the time
N(t) = 100 × (1/2) ^t/30
N(t) = 64 grams
64 = 100(1/2)^t/30
Divide both sides by 100
64/100 = 100(1/2)^t/30/100
0.64 = (1/2)^t/30
Take the Log of both sides
log 0.64 = log (1/2)^t/30
log 0.64 = t/30(1/2)
t = 19.315685693242 years
Approximately = 19.3 years
Answer: -2x + 5y = 8
Step-by-step explanation:
Since the lines must be parallel, the slopes must be the same, so keep the coefficients of x and y
Substitute the values of x and y from the given coordinate (6,4) to find the new constant, b, the y-intercept.
-2x + 5y = b
-2(6) + 5(4) = b
-12 + 20 = b
8 = b
Rewrite the original equation substituting the new b for the original -15
-2x + 5y = 8
14% of 82
14/100 = 0.14
0.14 * 82 = 11.48
Answer: 11.48
Answer:
only mixed number can be changed into improper fraction according to my khowlage of grade7
Step-by-step explanation:
thank you
