If the equations $2ax^2 - 3bx + 4c = 0$ and $3x^2 - 4x + 5 = 0$ have a common root,then $\left( \frac{a + b}{c} \right)$ is equal to (where $a, b, c \in R$).

If $\alpha$ and $\beta$ are the roots of the equation $x^2 + 6x + \lambda = 0$ and $3\alpha + 2\beta = -20$,then $\lambda = $

If $x=z=225$ and $y=226$,then find the value of $x^{3}+y^{3}+z^{3}-3xyz$.

If the equations $ax^2 + bx + c = 0$ $(a, b, c \in R, a \ne 0)$ and $2x^2 + 3x + 4 = 0$ have a common root,then $a : b : c$ equals

If $8, 2$ are the roots of ${x^2} + ax + \beta = 0$ and $3, 3$ are the roots of ${x^2} + \alpha x + b = 0$,then the roots of ${x^2} + ax + b = 0$ are

If the cost price of an article is $79 \frac{2}{7} \%$ of the marked price and there is a discount of $Rs. \,68$ on the marked price,resulting in a profit of $20 \%$,find the cost price (Quantity $I$) and compare it with a given value (Quantity $II = 1200$).