Answer :
[tex]W = No.\ of\ games\ won\\
L = No.\ of\ games\ lost\\\\W+L = 20----(1)\\\\
Also\ given\ that\\W = L+ 4----(2)\\\\Putting(2)\ in\ (1)\\\\(L+4) +L = 20\\2L = 20 -4\\2L= 16\\Divide\ both\ sides\ by\ 2,\ we\ get\\\\L =8----(3)\\\\Put\(3)\ in (2)\\W = 8 + 4\\\\W = 12\ \ Answer[/tex]