Compound Interest General Questions

CI = 8000 x (1 + 10/100)2 - 8000
= 8000 x (11/10) x (11/10) - 8000
= ₹ 9680 - 8000
= ₹ 1680

∴ Sum = (840 x 100)/(3 x 8) = ₹ 3500
[ ∵ SI is half of CI ]
∴ SI = 1680/2 = ₹ 840

Amount of Rs. 100 for 1 year
when compounded half-yearly

		= Rs.		100 x		1 +	3		2		= Rs. 106.09
							100

∴ Effective rate = (106.09 - 100)% = 6.09%

P

1 +

20

n

> 2P

⇒

6

n

> 2.

100

5

Now,		6	x	6	x	6	x	6		> 2.
		5		5		5		5

So, n = 4 years.

Difference in C.I. and S.I. for 2 years

= ₹ (696.30 - 660)

= ₹ 36.30

S.I. on ₹ 330 for 1 year = ₹ 36.30.

∴ Rate		100 x 36.30
		330 x 1

= 11%

Let P = ₹ 100. Then, S.I. ₹ 60 and T = 6 years.

∴ R =		100 x 60		= 10% p.a.
		100 x 6

Now, P = ₹ 12000. T = 3 years and R = 10% p.a.

C.I.	= ₹ 12000 x 1 + 10 3 - 1 100
	= ₹ 12000 x 331 1000
	= 3972.

Let the sum be ₹ P.

Then,		P		1 +	10		2	- P		= 525
					100

⇒	P			11		2	- 1		= 525
				10

⇒ P =		525 x 100		= 2500.
		21

∴ Sum = ₹ 2500.

So, S.I. = ₹		2500 x 5 x 4		= ₹ 500
		100

We have (A's present share) (1 + 4/100)⁷ = (B's present share) (1 + 4/100)⁹
∴ A's present share/B's present share = (1 + 4/100)² = (26/25)² = 676/625

Dividing ₹ 3903 in the ratio of 676 : 625
∴ A's present share = 676/(676 + 625) of ₹ 3903 = ₹ 2028
   B's present share = ₹ 3903 - ₹ 2028 = ₹ 1875