Which of the following are the true?(A) The cost of Rs. 7200, 8% stoc…

The correct answer is Option (2) → (A), (B) and (C) only

"Rs. 7200 stock" means stock of face value Rs. 7200. Its cost is the face value times the market price of Rs. 100 stock, divided by 100. The dividend rate (8%, 8.5%, 10%) does not affect the cost. At a 4% premium, Rs. 100 stock costs Rs. 104; at a 15% discount, it costs Rs. 85.

Rs. 7200 stock at Rs. 90:

    \( \displaystyle 7200\times\frac{90}{100}=\text{Rs. }6480 \)

Rs. 4500 stock at a 4% premium:

    \( \displaystyle 4500\times\frac{104}{100}=\text{Rs. }4680 \)

Rs. 6400 stock at a 15% discount:

    \( \displaystyle 6400\times\frac{85}{100}=\text{Rs. }5440 \)

So the Rs. 7200 stock at Rs. 90 costs Rs. 6480, the Rs. 4500 stock at a 4% premium costs Rs. 4680, and the Rs. 6400 stock at a 15% discount costs Rs. 5440.

Checking the statements

(A) The cost of Rs. 7200, 8% stock at Rs. 90 is Rs. 6480. — Correct. \( 7200\times\frac{90}{100}=6480 \).

(B) The cost of Rs. 4500, 8.5% stock at 4% premium is Rs. 4680. — Correct. \( 4500\times\frac{104}{100}=4680 \).

(C) The cost of Rs. 6400, 10% stock at 15% discount is Rs. 5440. — Correct. \( 6400\times\frac{85}{100}=5440 \).

(D) The cost of Rs. 7200, 8% stock at Rs. 90 is Rs. 5961.60. — Incorrect. This is the same stock as in (A), and its cost is Rs. 6480, not Rs. 5961.60.

CBSE Applied Mathematics (Class XII):
Stock, Shares and Debentures