Lupita can solve a Rubiks cube in 4 minutes. Her sister Liz is very fast and can solve 5 Rubik cubes in 12 minutes. Working together, what is the fewest number of minutes it will take for them to solve 10 cubes?

Find a general solution to the PDE +yyy where u = u(x,y) is the unknown function. (2.2) Consider the PDE tarpuu + 54 rue + 4**. - rue U=0 (a) Show that the solutions of the characteristic equations are given by 12-2= and 4t? - x = 0, (b) By using an appropriate transformation & = {(2,6), = (x,t), show that the initial (4) equation reduces to MEY 0. (c) Deduce a general solution for the given equation.