Full resolution (JPEG) - On this page / på denna sida - Logarithms - Compound interest by logarithms - Discount or rebate
<< prev. page << föreg. sida << >> nästa sida >> next page >>
Below is the raw OCR text
from the above scanned image.
Do you see an error? Proofread the page now!
Här nedan syns maskintolkade texten från faksimilbilden ovan.
Ser du något fel? Korrekturläs sidan nu!
This page has never been proofread. / Denna sida har aldrig korrekturlästs.
LOGARITHMS. 83
Solution by formula :
Log. a = n X log. r 4- log. p
Log. a = 6 X log. 1.04 + log. 816
Log. a = 6 X 0.017033+ 2.911690
Log. a = 0.102198 + 2.911690
Log. a = 3.013888
a = $1032.50 = Amount.
Example.
If $750 is invested at 3% compound interest, how many
years will it take before the amount will be $950.
Solution by formula
:
n = log, a — ’log, p
log. r
__ log. 950 — log. 750
~
log. 1.03
2.977724 — 2.875061
= 8 years (nearly).
0.012837
Example.
A principal of $3750 is to be invested so that by compound
interest it will amount to $5000 in six years. Find rate of
interest.
Solution by formula
:
Log_ r = log.a-log.p
n
T 3.698970 — 3.574031
Log. r =
6
Log. r = 0.020823
r = 1.0491
Rate of interest = lOOr— 100 = 100 X 1.0491 — 100 = 4.91% ;
or 5 % per year (very nearly).
Discount or Rebate.
When calculating discount or rebate, which is a deduction
upon money paid before it is due, use formula
:
p= JL
Log. p = log. a — n X log. r
<< prev. page << föreg. sida << >> nästa sida >> next page >>
