Since, milk and chocolate powder are in a ration of 5:2, assume that the weight of milk is 5x and weight of chocolate powder is 2x.
Weight of cookie= Weight of milk + Weight of chocolate powder= 5x+2x= 7x
Given that
Weight of cookie= 700 gm
7x= 700
x=100gm
Thus the weight of milk= 5x=5×100=500gm
Weight of chocolate powder =2x=2×100=200gm