Tungsten, w-181, is a radioactive isotope with a half life of 121 days. if a medical lab purchases 24 kg of w-181, how much will be left after 1 year? a) 24 kg b) 12 kg c) 6 kg d) 3 kg

The correct answer of this question is : 3 Kg

EXPLANATION :

As per the question, the half life period of W-181 :  

The initial amount of the specimen

We are asked to calculate the amount of specimen left after one year.

Hence, the total time t = one year = 365 days.

Hence, total number of half lives n =

                                                          =

                                                          =

                                                          = 3.

Let the amount left after one year is N.

Hence, the rest amount of specimen is calculated as-

                       ⇒

                                                   [ans][

emily ruth's annual premium is $1058.50

step-by-step explanation:

emily ruth is a female of 27 years age purchasing 20 year endowment insurance with face value $25000.

from the given table,

for females, the age of a male 3 years younger should be used.

so, we have to check for 24 year male for 20 year endowment.

it is 42.34 for every $1000 face value.

for a face value of $25000,

it is 25 * 42.34 = $1058.50

∴ emily ruth's annual premium is $1058.50

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