If solution a has twice as much solute as solution b is it possible for them to have the same concentration

The masses of solute in the 2 solutions can be different but result in the same concentration, this is best explained with examples. 
Say solution A contained 10g of solute and had a volume of 100dm^3
If solution B contained 5g of solute and had a volume of 50dm^3 this would make the concentrations of A and B identical.

If the water vapor content stays the same and the temperature drops, then the relative humidity increases. its vise versa.if the water vapor content stats the same and the temperature rises, the relative humidity decreases. so, yes, i'd say that temperature and humidity have a strong relationship.