Using Alligation Rule, the ratio of cost prices of desktop and laptop will be

Let the total cost be ₹50,000.
We are told that the cost of the desktop is \(\frac{2}{5}\) of the total cost.
So, the cost of the desktop is: \[ \text{Cost of desktop} = \frac{2}{5} \times 50000 \] Now calculate the product: \[ = \frac{2 \times 50000}{5} = \frac{100000}{5} = 20000 \] ∴ The cost of the desktop is ₹20,000.
Let D be the cost of the desktop and L be the cost of the laptop.
Add equations (2) and (3):
\[ 2D - L + D + L = 10000 + 50000 \] \[ 3D = 60000 \] \[ D = \frac{60000}{3} = \boxed{20000} \]
For any natural number $k$, let $a_k = 3^k$. The smallest natural number $m$ for which \[ (a_1)^1 \times (a_2)^2 \times \dots \times (a_{20})^{20} \;<\; a_{21} \times a_{22} \times \dots \times a_{20+m} \] is: