discrete math

A sick UCLA student from Dykstra residence hall visits a doctor at Health Center. The doctor already knows that 95% of sick people from Dykstra residence hall have Covid19, while the other 5% have the u. Let us assume that there is no other disease currently ailing people in Dykstra residence hall. A common early symptom of the u is a runny nose. The probability of someone having a runny nose if that pekson has the u is 0.90. Occasionally, Covid-19 also presents with the same symptom. Assume that the probability of someone having a runny nose if they have Covid-19 is 0.06. After examining the sick student, the doctor observes that they have a runny nose. What is the probability that the student has the u