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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Given,
CP of cosmetics = Rs 360 per dozen
SP of a pair of cosmetics = Rs 80
We need to find the profit percentage.
Solution,
We know that,
1 dozen = 12 items
CP of 1 cosmetic = 360/12 = Rs 30
SP of 1 cosmetic = 80/2 = Rs 40
Profit = SP-CP
= Rs 40 - Rs 30
= Rs 10
Profit percentage is given by :

So, the profit percentage is 33.34%.
Answer:
B.
Step-by-step explanation:
A/B × D/C = A/B × D/C because when we divide a fractional number we need to turn the second expression upside down .
Answer:
its d
Step-by-step explanation:
the number 30 is not listed in the problem there that is info that is not there