If a cashier can count a certain sum of cash in 2 hours and another cashier can count the same sum in 3 hours then both cashiers working together will count this sum in what

36x2 + 49y2 = 1,764 the foci are located at: (-√13, 0) and (√13,0) (0, -√13) and (0,√13) (-1, 0) and (1, 0)edit: the answer is (- the square root of 13, 0) and (the square root of 13, 0)