Two cards are draw from a well shuffled pack o cards one after the other without replacement. Find the probability that one of these is a queen and the other is a king of oppoite colour.

total number of cards =52

in 52 cards there are 4 queens and 4 kings.

2 queens and 2 kings are of red color and 2queens and 2kings are of black color.

 here we need to find the probability that one is queen and other is king of opposite color.

this can happen in two ways, 

case 1: first card is queen and 2nd card is king.

case 2: first card is king and 2nd card is queen.

required probability=