A sum rs 1200 becomes rs 1323 in a year at compound interest half yearly Find rate of interest - Maths - Quadratic Equations

Question

A sum rs 1200 becomes rs 1323 in a year at compound interest half
yearly Find rate of interest using quadtratic equation

Ankita Agarwal · Accepted Answer

Dear Student,

Suppose the rate of interest per annum is R%
Since the interest is compounded Half yearly;so number of times interest compounded is n=
2WhenT=
1year ,then amount accumulated after 1 year is given by;A=P1+Rn×100n×T1323=12001+R200213231200=1+R200213231200=200+R20021323×200×2001200=200+R244100=40000+R2+400RR2+400R-4100=0using  qudratic formula=-b±b2-4ac2a , where a=1 , b=400 and c=-4100=-400±4002-4×-41002=-400±160000+164002=-400±1764002=-400±4202R=-400+4202 , -400-4202    =10 , -410 Ignoring negative Rate of interestSo , R=10%

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A sum rs 1200 becomes rs 1323 in a year at compound interest half yearly. Find rate of interest using quadtratic equation