First, let's check how you have defined the events. The problem was:
Probability that Bayern Monachium wins an away match is equal to 0.6.
Probability that Bayern Monachium wins a match and Lewandowski scores at least one goal is equal to 0.25.
What is the probability that Lewandowski scores in an away match under the condition that Bayern wins the match?
You wrote:
P(W) = 0.6
P(S) = 0.25
P(W∩S) = P(0.6∩0.25)
P(S|W) = ?
But you surely meant to define
W = Bayern Monachium wins an away match
S = Lewandowski scores at least one goal
If so, then it is not true that P(S) = 0.25. What is the probability that equals 0.25?
Also, note that P(0.6∩0.25) is meaningless; what goes inside the parenthesis is an event, not a couple numbers connected with "and".
Note: This is essentially what Jomo said, but since I put in the time to transcribe the problem and work (which you could have done, to make it easier for us to interact with you), I'm still posting it.
Once you get the statements right, you will want to express them in terms of the definition of conditional probability, and will almost have the answer.