A reversible aqueous reaction A + B = C + D is at equilibrium with [A], [B], [C], and [D] concentrations of 10, 30, 60, and 40 mole/L respectively. If concentration of [D] is suddenly doubled, calculate the concentrations for all constituents (to the nearest 1 molar unit) when the system returns to equilibrium. (Hint: Calculate Keq and Keq will remain constant. You can choose to show hand calculations of stepwise changes (one reaction per step) from the disturbed state to the new equilibrium state; otherwise, you can choose to assume x amount of [D] and [C] will react to form x amount of [A] and [B] and solve a Quadratic Equation.