Mahindra Comviva Simple and compound interest Problems with Solutions Quiz -1

Amount = Rs [7500*(1+(4/100)2] = Rs (7500 * (26/25) * (26/25) ) = Rs. 8112.
therefore, C.I. = Rs. (8112 - 7500) = Rs. 612.

Amount = pleft ( 1+frac{R}{100}
ight )^{t}
= 8000left ( 1+frac{15}{100}
ight )^{2frac{1}{3}}
= 8000left ( 1+frac{3}{20}
ight )^{2}left ( 1+frac{3}{20 imes 3}
ight )
= 8000 imes frac{23}{20} imesfrac{23}{20} imesfrac{21}{20}
= Rs. 11109
∴ Compound Interest = Rs. (11109 – 8000) = Rs. 3109
Hence option [A] is the right ansew

A=10000left ( 1+frac{2}{100}
ight )^{4}
=>10000left ( frac{51}{50}
ight )^{4}
=>10000left ( 1.08243216
ight )=10824.3216
Since Interest = 10824.3216 – 10000 = Rs.824.32
Hence option [C] is the right answer.

Principle = Rs.16000, Time = 9 months = 3 quarters
Rate = 20% per annum = 5% per quarter
=> Amount = Rs. [16000*(1+5/100)^3)]
= Rs.16000 * 21/20 * 21/20 * 21/20 = Rs. 18522
CI = Rs. (18522 - 16000) = 2522

In what time will Rs. 1000 become Rs. 1331 at 10% per annum compounded annually?

Principal = Rs.1000;
Amount = Rs.1331;
Rate = Rs.10%p.a.

Let the time be n years then,

1000(1+10100)n=1331(1110)n=13311000(1110)3=13311000

So answer is 3 years

Principal = Rs. 500; Amount = Rs. 583.20; Time = 2 years.Let the rate be R% per annum.. 'Then,[ 500 (1+(R/100)2 ] = 583.20 or [ 1+ (R/100)]2 = 5832/5000 = 11664/10000[ 1+ (R/100)]2 = (108/100)2or 1 + (R/100) = 108/100 or R = 8So, rate = 8% p.a

Let the sum be Rs. x. Then,


C.I. = [ x * (1 + (( 50/(3*100))3 - x ] = ((343x / 216) - x) = 127x / 216


127x /216 = 1270 or x = (1270 * 216) / 127 = 2160.


Thus, the sum is Rs. 2160


S.I. = Rs ( 2160 * (50/3) * 3 * (1 /100 ) ) = Rs. 1080.

Let the sum be Rs. x. Then,
C.I. = x ( 1 + ( 10 /100 ))^2 - x = 21x / 100 ,
S.I. = (( x * 10 * 2) / 100) = x / 5
(C.I) - (S.I) = ((21x / 100 ) - (x / 5 )) = x / 100
( x / 100 ) = 632 * x = 63100.
Hence, the sum is Rs.63,100.

Let the rate be R% p.a. Then,



[1800(1+R100)2−1800]−(1800*R*2100)=405
1800[(100+R)210000−1−2R100]=405
1800[(100+R)2−10000−200R10000]=405
⇔
95*R2=405 ⇔R2=(405*59)=225⇔R=15
Rate = 15%