Let the principal be P,then
P(1 + R/100)³ = 6690
And P(1 + R/100)⁶ = 10,035
Now, dividing (ii)by (i),we get
⇒ (1 + R/100)³ = 10035/6690 = 3/2

Correct Option: C

Let the principal be P,then
P(1 + R/100)³ = 6690
And P(1 + R/100)⁶ = 10,035
Now, dividing (ii)by (i),we get
⇒ (1 + R/100)³ = 10035/6690 = 3/2
⇒ P x 3/2 = 6690
∴ P = (6690 x 2/3 ) = Rs. 4460

Yearly interest = 10%
Half yearly = 5%
Time = 1¹/₂ = (3/2) x 2 half yearly = 3 half yearly
Amount = 8000(1 + 5/100)³
= 8000 x (21/20)³
= 8000 x 21/20 x 21/20 x 21/20
= Rs. 9261

Correct Option: A

Yearly interest = 10%
Half yearly = 5%
Time = 1¹/₂ = (3/2) x 2 half yearly = 3 half yearly
Amount = 8000(1 + 5/100)³
= 8000 x (21/20)³
= 8000 x 21/20 x 21/20 x 21/20
= Rs. 9261

Compound interest = Amount - Principal = 9261 - 8000
= Rs. 1261

S.I. or C.I. for first year are always equal
Principle = (S.I. x 100)/(Rate x Time)
= (48 x 100)/(8 x 1) = Rs. 600
Interest for second year = Amount of second year - Amount of the first year
= 600 (1 +8/100)² - 600(1 +8/100)

Correct Option: B

S.I. or C.I. for first year are always equal
Principle = (S.I. x 100)/(Rate x Time)
= (48 x 100)/(8 x 1) = Rs. 600
Interest for second year = Amount of second year - Amount of the first year
= 600 (1 +8/100)² - 600(1 +8/100)
= 600(27/25)² - 600(27/25)
= 600(27/25) {27/25 - 1}
= 600(27/25) (2/25)
= Rs. 51.84

∵ 328 = Principal {(1 +5/100)² - 1}
⇒ 328 = Principal (441/400 - 1)
⇒ 328 =Principal 41/400
⇒ Principal = (328 x 400)/41 = Rs. 3200
∴ Simple interest = (3200 x 5 x 2) / 100 = Rs. 320

Correct Option: A

∵ 328 = Principal {(1 +5/100)² - 1}
⇒ 328 = Principal (441/400 - 1)
⇒ 328 =Principal 41/400
⇒ Principal = (328 x 400)/41 = Rs. 3200
∴ Simple interest = (3200 x 5 x 2) / 100 = Rs. 320

Here P(1+20/10)^t > 2P
⇒ (6/5)^t > 2

Correct Option: C

Here P(1 + 20/10)^t > 2P
⇒ (6/5)^t > 2
∵ (6/5)³ = 1.728, and
(6/5)⁴ = 2.0736
By trial (6/5) x (6/5) x (6/5) x (6/5) > 2
∴ The required time is 4 years.