What percent of 31 is 48 if necessary round your answer to the nearest hundredth of percent

Aclass consists of 55% boys and 45% girls. it is observed that 25% of the class are boys and scored an a on the test, and 35% of the class are girls and scored an a on the test. if a student is chosen at random and is found to be a girl, the probability that the student scored an ais

Need on this one asap im almost done with this subject

Mat bought a phone for $100. he has to pay $30 per mouth. if he has paid $640 in total, how many mouth has he had the phone?