The si on a certain sum at a certain rate in 3 year is 78 and the ci in 2 year is 53 .find the rate.

Asked by beheraswagatika001 | 5th Mar, 2019, 05:53: AM

Expert Answer:

Let p is principle and r is rate of interest
 
Simple interest : (p×3×r)/100 = 78    or    p×r = 2600 ...................(1)
 
Compound Interest : begin mathsize 12px style p open parentheses 1 plus r over 100 close parentheses squared space equals space p plus space 53 end style
begin mathsize 12px style p space plus space fraction numerator p r squared over denominator 10000 end fraction plus fraction numerator p r over denominator 50 end fraction space equals space p space plus 53 space space................... left parenthesis 2 right parenthesis

s u b s t i t u t i n g space space p r space equals space 2600 space a s space g i v e n space i n space e q n. left parenthesis 1 right parenthesis space comma space space e q n. space left parenthesis 2 right parenthesis space space i s space w r i t t e n space a s

fraction numerator 2600 cross times r over denominator 10000 end fraction space plus space 2600 over 50 space equals space 53 space space space space space space o r space fraction numerator 26 space r over denominator 100 end fraction space equals space 1 space space space space space o r space space space r space equals space 100 over 26 space almost equal to space 4
end style

Answered by Thiyagarajan K | 5th Mar, 2019, 09:37: AM

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