Prasanjeet Mohanty Mohanty
Last Activity: 14 Years ago
In giving a signal, the order of the placement of colours is important,i.e a red and blue signal is different than the blue and red signal. Hence the order is very important.
Therefore the required no. of ways=4P1 +4P2 +4P3 +4P4 =4+12+24+24=64