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
#SPJ1
Answer:
Step-by-step explanation:
let : x the length and y the width .... ( x > y and x ; y reals numbers )
the perimeter is : 2(x+y)
2(x+y) = 55...(1)
x/y = 7/4 ...(2)
by (2) : x = (7/4)y
subsct in (1) : 2( (7/4)y +y ) =55
(7/2)y +2y =55
multiply by 2
7y +4y = 110
11y = 110
y = 10
x = (7/4)(10)
x = 35/2
Answer:
B
Step-by-step explanation:
5^2 - 3^2 = 4^2 So you know that 4 is the height. 4^2 + 7^2 is 65. Find the square root. Square root of 65.
