Therefore to be the integral value x must be 4m; m = 1, 2, 3 ... So, at m = 1 Hence option (a) is correct since B had contributed 1 number. Initial amount A7​B5​C4​D0​ Final amount 43​41​40​4​ ∵ B had contributed 1 soda water, therefore B got ₹ 15.