Compound Interest
6.
What is the different between compound interest and simple interest for 2 yr on the sum of Rs 1250 at 4% pa?
A.
Rs. 3 B.
Rs. 4 C.
Rs. 2 D.
Rs. 8

Answer: Option C

Explanation: Given that p = 1250, n = 2 yr R = 4%
Different between compound interest and simple interest PR2/ 1002
Required difference = 1250 x 4 x / 100 x 100 = 2

7.
The simple interest for cercter sum in 2 yr at 4% pa is Rs 80. What will be the compound interest for the same sum, if condition of rate and time period are same?
A.
90.60 B.
81.60 C.
71.60 D.
80

Answer: Option B

Explanation: Given that n = 2 yr, R = 4% SI = 80
According to the formula
CI = SI (1 + R /100)
= 80 (1+ 4/200) = 80 x 51 /50
= 81.60

8.
At what rate of compounded interest pa will a sum of Rs 2400 become Rs 2696.64 in 2 yr?
Answer: Option A

Explanation: According to the formula
Amount = P (1 + R /100)^{n}
2696.64/2400 = 2400 (1 + R /100)^{2}
2696.64/2400 = (1+ R/100)^{2}
(1+ R/ 100)2 = 11236/ 10000
(1+ R /100 )2 =(106/100)^{2}
1 + R/100 = 106/100
R/100 = 106 /100 â€“ 1
= 106 â€“ 100 /100 = 6/100
= 6

9.
An amount at the rate of 5% pa become Rs 10 more at compound interest than that of simple interest after 2yr. calculate the principal.
A.
Rs. 4000 B.
Rs. 4050 C.
Rs. 4150 D.
Rs. 4200

Answer: Option A

Explanation: Given that CI â€“ SI = 10, R = 5%, n = 2 yr P = ?
According to the formula
CI â€“SI = PR2/1002
10 = p x 25/10000
P = 400 x 10
= 4000

10.
If Rs 3000 amounts to Rs 4320 at compound interest in a certain times, than Rs 3000 amounts to what in half of the times?
A.
Rs. 3400 B.
Rs. 3550 C.
Rs. 3500 D.
Rs. 3600

Answer: Option D

Explanation:

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