Abaseball player get on base seven times and strikes out five times during the tournament. what is that experimental have ability of the player getting on base?

First you have to make the assumption that these are the only two outcomes. There is also the possibility of hitting the ball and getting out. 

However, if we assume that these are the only two cases, we know that the probability is 58.3%. This is because it has been on base 7 times out of 12.