Question:The difference between the compound interest and the simple interest on a sum of money for two years at `12 1/2 %` per annum is Tk. 150 The sum is:
A Tk. 9000
B Tk. 9200
C Tk 9500
D Tk 9600
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+ Answer
D
+ ExplanationLet the sum be Tk. `x.` Then,
C.I.
`= x ( 1 + 25/(2 xx 100))^2 - x `
`= (9/8 xx 9/8)x - x`
`= (17x)/64`
S.I. =`( x xx 25/2 xx 1/100)`
` = x/4`
(C.I) - (S.I)
`= ((17x)/64 - x/4)`
`= x/64`
`:. x/64`
`= 150`or
`x=9600`