Answer=7:13
Kenny's Weight*6/7=Melvin's Weight
So, for example, if Melvin's weigh was 7...
Kenny's Weight*6/7=7
divide both sides by 6/7
Kenny Weight=6
So we can say that Melvin's weight to Kenny's weight is 7:6
The boys total weights would be...
7+6=13
So Melvin's weight over the total weight of the two boys is:
7:13