The question involves a ping-pong ball that is held submerged in a bucket by a string attached to the bottom of the bucket.
The answer is the tension of the string will increase. This is because making the water salty increases its density, and consequently, increases its buoyancy. This is why sea water is more buoyant than fresh water. Therefore the ping pong is pushed more upwards by the water when salt is added than initially. This gives the string more tension.
