The annual premium paid is 10% of the new value = P/10 ,
where P is the new value of the machine.
The value of the
machine due to depreciation is 1/2 of new value for every two years. Thus the machine
value at any year becomes sqrt(1/2) of its pevious year value. The new value of the
machine is P . So after n years the value of the machine becomes {sqrt(1/2)} ^n * P=
P/(2^(n/2)).
So the maximum pay out by the insurance
company at any year = machine value at that time (or year) =
P/(2^(n/2)).
So it is required to determine when the
maximum pay out by the insurance company becomes less than the annual premum
.
Therefore to determine n such that P/2^(n/2) <
P/10.
Divide by P and cross
multiply:
10 <
2^n/2.
log10 < (n/2)
log2.
2 /log2 > n.
Or n
> 2/log2 .
Clearly for n = 6.64 , 1/2(6.64/2) =
0.100226.. > 1/10.
For n = 6.65 , 1/2^(6-65/2) =
0.9979 < 1/10.
Therefore between the year 6 and 7
(or between 6.64 years and 6.65 years, or in the 8th month after 6 years) the maximum
insurance becomes less than the annual premium. So making the annual payment of premium
is a clear loss from the 7th year onwards.
No comments:
Post a Comment