The Republican journal., 1888-05-03
Interesting to Teachers.

There is Il problem in the Fi>h-RobinSon
under Art. 192. that hu$ been Il source of un-
ending distress to Us as teachers, and IS H0tc
to many. How many teachers have worked at
this to get sdttStact0Fy explanation for it
satisfactory not to the scholar alone, but to the
teacher himself; for the scholar is satisfied
with almost anything that will get him over
this problem regardless of the logic of the eX-
planation. Truth to tell, think the most of
us went to our Keys and took the work there
as we found it, and got through the eXplana-
ton the best way We could | did. How
many Others did: Hands up.
He is an old enemy of ours. What con-
sternation he carried into our ranks when first
We knew him. He has appeared TO Us and ap-
paled the >toute>t; appeared at the most un-
welcome and announcement times and places :
not even the day ul The cuD,ntttcc'S visit wa,
holy time; but like Banquo> ghost he appear
ed to lis, and if he had been capable Of being
murdered would have had equal cause with
Banquo's ghost, though the ertrente proroco-
ton would have >oothcd our conscienceS.
feel that have laid this ghost and it may
be of interest to others to know the spell if he
has haunted them As he has me lie looms up
to us in this form:
A man bought farm for So 900 and agreed
to pay principal and interest in three equal an
nua in>talmentS. What was the annual uaV-
ment. interest being PEI cent:
Now this means simply that he would make
Que payment at the end of the first year: one
at the end of the second year. and one at the
end of the third year. ,ea,h payment to be The
sameJ and the value of the three payments is
to he equal To $1,000 NoW or in other words
$4,000 is the PRESENT WORTH Of these three
payments.
Rightly understanding this, the problem is
simple one. Let Us find first the present
moHh of one dollar paid at each of these srv-
eral times, rechoning compouAd itereSt. To
find the present worth of any sum due at f,l-
ture time (reckoning compouHd iatprrSt we
Of course divide that sum by the amount of
one dollar at compound interest for the entire
time, therefore:
The pres. worth of 81 due wear
hence=Sl divided by SlWi=SA ls53
The pres. worth of II due years
hence=Sl divided by 81 .l236- IS 3s0> 2so9
The pres. worth of 81 due years
hence=Sl divided by $l.l9lOl6- .S3 ll320y- l4Ss77
Total. l............ 500 50509 l4sS77
This means that should he pay one dollar
each year for three years it would be cquiva-
lent to S2,G7 50509-14Ss11 paid cash down; that
is it is the present ecorM of three annual pay
ments of one dollar each. reckoning conp0und
interest; in other words three such payments
discharge a present Indebtedness of S2.67
50509-14SS111. But he has a present indebted
ness of $4,000 to discharge, and the question
becomes now: If an annual payment of 81
each year for three years. will discharge a
present debt of $2.67 505O9-l4S what must
be the annual payment that will discharge Il
present Indebtedness of $4,000?
Stated -S2.67 5o509- ASST 6oOo=sl: { J.
Solved $4,000 divided by %. 50509 li>s71=S2,
1866, Ans.
This is submitted, not with any idea of in
structing the other teachers in Waldo county,
but in the hope that it may prove helpful. The
business practice would be to pay one payment
cash down, one at end of first year, and one at
answer is S2,117.63.
The thing may be practically arrived at In a
much shorter way: If the payment of $4,000
were made cash down at the end of 3 years it
would amount to S7,l46.10. Now the three
payments must be such that if put at COM
pound interest at per cent. when made they
will amount to 81, 46.10 at end of third year.
First payment made at end of first year has .
years to run, and second has one year and
third is made when due. A payment of 81
made at each of these times would discharge
an Indebtedness of ($1.1236 plus S1.O6 plus 81
S3.1S3G. But there is a debt of S7,146.1O.
Question is If one dollar paid each year
pays debt of $3. 1886, how much must be paid
each year to pay debt of S7,1461O? State and
solve. A TEACHER.