The percentage of the radioactive isotope left is 25.0000%.
<h3>What is the half life?</h3>
The half life of a radioactive isotope is the time that will elapse before only half of the number of original isotopes will remain.
Now;
We are told that;
Half life (t1/2) = 55 days
Time taken (t) = 115 days
Ratio of isotope remaining = N/No
Thus;
N/No = (1/2)^t/t1/2
N/No = (1/2)^115/55
N/No = (1/2)^2
N/No =1/4
Hence, the percentage = 1/4 * 100/1 = 25.0000%
Learn more about half life of an isotope:brainly.com/question/16387602
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Answer:
Step-by-step explanation:
B
82 tens in the same thing as 820 because if you multiply 82 by 10 you get 820
Answer:
see below
Step-by-step explanation:
To find the combined length of Pine and Elm and the lengths together
Pine +Elm
We are estimating by rounding to the nearest whole number
Pine is 2.7 so it rounds to 3 because we look at the .7 and since .7 is greater than .5 it rounds the 2 to 3
Elm is 8.9 so it rounds to 9 because we look at the .9 and since .9 is greater than .5 it rounds the 8 to 9
2.7 + 8.9 rounds to 3+9 = 12
12 is reasonable because the actual answer is 2.7+8.9 = 11.6 which rounds to 12
Answer:
y=3
Step-by-step explanation:
This is an isosceles triangle because the two angles at the bottom are equal.
This means the two sides are equal
5y-2 = 13
Add 2 to each side
5y-2+2 =13+2
5y = 15
Divide each side by 5
5y/5 = 15/5
y =3
