Question: If the simple interest on a sum of money at 5% per annum for 3 years is Tk. 1200, the compound interest on the same sum for the same period at the same rate, is:
A
Tk. 1260
B
Tk. 1261
C
Tk. 1264
D
Tk. 1265
Note: Sum=Tk. `((100 xx 1200)/(3 xx 5))` = Tk. 8000
Amount = Tk. `[8000 xx (1 + 5/100)^3]`
Tk. = `(8000 xx 21/20 xx 21/20 xx 21/20)`
`:.` C.I. = Tk. (9261 - 8000) = Tk. 1261
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
Note: Let 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`
Question: If the difference between the compound interest, compounded half yearly and the simple interest on a sum at 10% per annum for one year is Tk. 25, the sum is:
A
Tk. 9000
B
Tk 9500
C
Tk 10000
D
10,500
Note: Let the sum be Tk. `x.` Then,
C.I. = `x(1 + 5/100)^2 - x = ((441x)/400 - x) = (41x)/400.`
S.I. = `(x xx 10 xx 1)/100 = x/10`
(C.I) - (S.I) = `(41x)/400 - x/10 = x/400`
`:. x/400 = 25 or x = 10000`
Hence, the sum is Tk. 10000.
Question: If the simple interest on a sum of money at `5%`per annum for `3` years is Rs.`1200`, the compound interest on the same sum for the same period at the same rate, is :
A
`Rs. 1260`
B
`Rs. 1261`
C
`Rs. 1264`
D
`Rs. 1265`
Note: Sum`= Rs.((100 xx 1200)/(3 xx 5))`
`= Rs. 8000.`
Amount`= Rs.[ 8000 xx ( 1 + 5/100)^3]`
`= Rs.( 8000 xx 21/20 xx 21/20 xx 21/20)`
`= Rs. 9261`
:. C.I.`= Rs. (9261 - 8000)`
`=Rs. 1261`.
Question: The difference between the compound interest and the simple interest on a sum of money for `2` years at `12 1/2%`per annum is Rs.`150`.The sum is :
A
`Rs. 9000`
B
`Rs. 9200`
C
`Rs. 9500`
D
`Rs. 9600`
Note: Let the sum be Rs.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 2 xx 1/100)`
`= x/4`
`(C.I.) - (S.I.) = ((17x)/64 - x/4)`
`= x/64`
`:. x/64 = 150`
`or x = 9600`.
Question: If the difference between the compound interest, compounded half yearly and the simple interest on a sum at `10%` per annum for one year is Rs.`25`,the sum is :
A
`Rs. 9000`
B
`Rs. 9500`
C
`Rs. 10000`
D
`Rs. 10500`
Note: Let the sum be Rs.x. Then,
C.I.`= x (1 + 5/100)^2 - x`
`= ((441x)/400 - x)`
`= (41x)/400`
S.I.`= (x xx 10 xx 1)/100`
`= x/10`
(C.I) - (S.I)`= (41x)/400 - x/10`
`= x/400`
`:. x/400 = 25`
`or x 10000`.
Question: A man borrowed Rs. `800`at `10%` per annum simple interest and immediately lent the whole sum at `10%` per annum compound interest. What dose he gain at the end of `2` years ?
A
`Rs. 6`
B
`Rs. 8`
C
`Rs. 10`
D
`Rs. 12`
Note: C.I.= Rs.` [ 800 xx (1 + 10/100)^2 - 800]`
`= Rs. 168.`
S.I. Rs.`((800 xx 10 xx 2)/100)`
`= Rs. 160`
Gain = (C.I) - (S.I)
`= Rs. (168 - 160)`
`= Rs.= 8`
Question: On what sum of money will the simple interest for `3` years at `8%` per annum be half of the compound interest on Rs.`400` for `2` years at `10%` per annum ?
A
`Rs. 125`
B
`Rs. 150`
C
`Rs. 175`
D
`Rs. 200`
Note: C.I. on Rs.`400` for `2` years at `10%` p.a.
`= Rs. [400 xx (1 + 10/100)^2 - 400]`
`= Rs. 84`
required S.I.`= 1/2 xx Rs. 84`
`= Rs. 42`.
Now S.I.` = Rs. 42,`Time`= 3`years & Rate` = 8%`
`:. sum` `= Rs.((100 xx 42)/(3 xx 8))`
`= Rs. 175`