A trader bought a camera at a price that allowed for a 20% profit. He then sold it at a discount of 10% on the marked price of Ksh 2400. Find the cost price of the camera.

The marked price (MP) is Ksh 2400.
The discount is 10% of the marked price.

The selling price is the marked price minus the discount amount.

The trader makes a profit of 20% on the cost price.
This means the selling price is the cost price plus 20% of the cost price.

We have the selling price from Step 1 and the relationship from Step 2.

To find the cost price, divide the selling price by 1.20.

The cost price of the camera is $\boxed{\text{Ksh 1800}}$.

The denominator is a difference of squares, $4a^2 - b^2$.

The numerator is $a^2 - 3ab - 2b^2$.
To factor this quadratic expression, we look for two numbers that multiply to $1 \times (-2) = -2$ and add up to $-3$. The integer pairs that multiply to -2 are (1, -2) and (-1, 2). Their sums are $1 + (-2) = -1$ and $-1 + 2 = 1$. Neither sum is -3.
Therefore, the numerator $a^2 - 3ab - 2b^2$ does not factor into simple linear terms with integer coefficients that would allow cancellation with the denominator's factors $(2a-b)$ or $(2a+b)$.

Since there are no common factors between the numerator and the denominator, the expression cannot be simplified further by cancellation. The most simplified form involves factoring the denominator.