Two particles P and Q get 6m closer each second, while travelling is opposite directions. They get 2.4 m closer every second while travelling in the same direction. The speeds of P and Q are
(1) 4.2 ms-1 and 2.4 ms-1
(2) 8.4 ms-1 and 3.6 ms-1
(3) 4.2 ms-1 and 1.8 ms-1
(4) 4.2 ms-1 and 3.6 ms-1
