Question

Why does a apricot do not sweel in salt solution and does in simple water?

Answer 1

The key piece of information here is that the apricots have been dried. In other words, most water has been removed from the fruit; they have been dehydrated. Imagine that there is still a tiny amount of water (containing dissolved solutes) inside the apricot. This would essentially be isotonic with the hyperosmotic salt solution, so very little to no movement of water would take place. However, plain water would be extremely hypoosmotic to the inside of the apricot, so it will move into the fruit until isotonicity between the two is established, causing the apricots to swell in the process. 

The only reason I disagree with EREX94's answer is that I find it very unlikely that any additional water will diffuse out of the apricots into the salt solution, considering that there is so little present. Even if it did, it would almost be volumetrically negligible. It makes more sense to me to rationalize that the two are essentially isotonic