You may not marry the first man or girl you meet because you may get a better one later. You cannot also wait for a long time till your hairs become gray. So what is the optimum time you have to wait? or what is the optimum number of persons you have to scrutinize? Here mathematics comes to our help.
Let us assume that you are able to encounter 'n' {say 60} persons as your prospective bride or groom in a span of one year.
Say, you come across a first person. What is the chance of selecting him or her ? Also what is the chance of rejecting? The probability theory says the chance of selecting is 1/n =1/60=0.017. The probability of rejecting is [1-1/n] =[1-.017]=0 .983
You come to know a second person. What is the chance of rejecting both. The multiplication rule tells it is, [1-1/n]* [1-1/n] = 0.983*0.983 = 0.966.
If you meet 3 persons in a row, the chance of rejecting all the 3 = [1-1/n]*[1-1/n]*[1-1/n] = [1-1/n]^3 = 0.983^3 = 0.949
Hence the formula for calculating 'the chance of rejecting all the n persons you meet' = [1-1/n]^n = [1-1/60]^60 = 0.983^60 = 0.357.
Suppose, you can meet 80 persons, what is the chance of rejecting all?
= [1-1/80]^80 = 0.987^80 = 0.351
for 100 persons
= [1-1/100]^100 = 0.37
for 200 persons,
=[1-1/200]^200 = 0.367
As a number of persons[n] increases "the chance of rejecting all" stabilizes on 0.368 or 0.37 or 37%, the magic number. What it means? If you really want to select one out of n persons, you can safely reject first 37% of persons and select the very next person who is better than all the previously seen persons. [Rejecting more than or less than 37% may be a 'risk'].
Out of 60 persons , you can ignore the first 22 persons and settle for the next best one. This 37% rule can be applied to many real life situations.
For a man, the youthful years are from age 18 to 40. 22 years in total. 37% of 22 years is 8 years. So one can let pass the 8 years from age 18 and get married in 26th year. So mathematics says 26 is the ideal age for marriage of a man.
37% rule can be used to buy house or rent apartments. The rule tells us when to stop the searching and gives us optimum.
I am not asking you to stick to mathematics strictly for making life's decision. But you can take it as a guide and aid for making difficult decisions.
By the way, 0.368=1/e where e= 2.71.. the mathematics constant. The e appears everywhere in maths and physics.
interesting! loved the way you brought the Euler's number in real life problems. However , percentage is a dangerous concept! it depends on the sample size and in real life we are not sure of the exact number of sample size we would have in future.
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