An email provider is developing a new spam filter to be used with their email service. Among all emails processed by the email service, 10% are known to be spam. For any spam email, the probability that the new spam filter correctly classifies the email as spam is 0.64 and for any legitimate email, the probability that the new spam filter incorrectly classifies the email as spam is 0.25.

Suppose a randomly seleted email is classified as a legitimate email by the new spam filter. Find the probability that the email was actually spam.

Please explain it step by step