Here, n = 2, T = 10 yr
∴ R = 100 (n - 1)/T

Correct Option: C

Here, n = 2, T = 10 yr
∴ R = 100 (n - 1)/T
= 100(2 - 1)/10
= 100/10
= 10%

Let sum = P
Then, according to the question.
SI = P/2
∴ P/2 = (P x 8 x 6)/100

Correct Option: D

Let sum = P
Then, according to the question.
SI = P/2
∴ P/2 = (P x 8 x 6)/100
∴ It is clear that data is inadequate.

Let the sum be P.
∵ SI = P/2
∴ P/2 = (P x 9 x 5)/100

Correct Option: D

Let the sum be P.
∵ SI = P/2
∴ P/2 = (P x 9 x 5)/100
Clearly data is inadequate.

If the sum be ₹ P, then
(2240 - P) = (P x 4 x 3)/100
⇒ 2240 = 12P/100 + P
⇒ 2240 = 112P/100
∴ P = (2240 x 100)/112 = ₹ 2000

Now, required interest,
SI = PRT/100 = [{2000 x (7/2) x (1/2)} /100]

Correct Option: C

If the sum be ₹ P, then
(2240 - P) = (P x 4 x 3)/100
⇒ 2240 = 12P/100 + P
⇒ 2240 = 112P/100
∴ P = (2240 x 100)/112 = ₹ 2000

Now, required interest,
SI = PRT/100 = [{2000 x (7/2) x (1/2)} /100]
= ₹ 35

Since, the two simple interest are equal.
Then, (4000 x 3 x R)/100 = (5000 x 12 x 2)/100

Correct Option: D

Since, the two simple interest are equal.
Then, (4000 x 3 x R)/100 = (5000 x 12 x 2)/100
∴ R = 10%