In Figure observer S detects two flashes of light. A big flash occurs at x1 = 1200 m and, 5.00s later, a small flash occurs

In Figure observer S detects two flashes of light. A big flash occurs at x1 = 1200 m and, 5.00μs later, a small flash occurs at x2 = 480 m. As detected by observer S', the two flashes occur at a single coordinate x'.
(a) What is the speed parameter of S', and
(b) Is S' moving in the positive or negative direction of the x axis? To S',
(c) Which flash occurs first and
(d) What is the time interval between the flashes?